diff --git a/core/src/main/java/com/google/bitcoin/core/Wallet.java b/core/src/main/java/com/google/bitcoin/core/Wallet.java
index f1a18d420..d76245459 100644
--- a/core/src/main/java/com/google/bitcoin/core/Wallet.java
+++ b/core/src/main/java/com/google/bitcoin/core/Wallet.java
@@ -208,6 +208,10 @@ public class Wallet extends BaseTaggableObject implements Serializable, BlockCha
         this(params, new KeyChainGroup());
     }
 
+    public static Wallet fromSeed(NetworkParameters params, DeterministicSeed seed) {
+        return new Wallet(params, new KeyChainGroup(seed));
+    }
+
     // TODO: When this class moves to the Wallet package, along with the protobuf serializer, then hide this.
     /** For internal use only. */
     public Wallet(NetworkParameters params, KeyChainGroup keyChainGroup) {
diff --git a/core/src/main/java/com/google/bitcoin/crypto/MnemonicCode.java b/core/src/main/java/com/google/bitcoin/crypto/MnemonicCode.java
index 8e2585d5c..179a68e13 100644
--- a/core/src/main/java/com/google/bitcoin/crypto/MnemonicCode.java
+++ b/core/src/main/java/com/google/bitcoin/crypto/MnemonicCode.java
@@ -42,6 +42,9 @@ public class MnemonicCode {
 
     public static String BIP39_ENGLISH_SHA256 = "ad90bf3beb7b0eb7e5acd74727dc0da96e0a280a258354e7293fb7e211ac03db";
 
+    /** UNIX time for when the BIP39 standard was finalised. This can be used as a default seed birthday. */
+    public static long BIP39_STANDARDISATION_TIME_SECS = 1381276800;
+
     private static final int PBKDF2_ROUNDS = 2048;
 
     public MnemonicCode() throws IOException {
diff --git a/tools/src/main/java/com/google/bitcoin/tools/WalletTool.java b/tools/src/main/java/com/google/bitcoin/tools/WalletTool.java
index 525556f96..b5c0018f8 100644
--- a/tools/src/main/java/com/google/bitcoin/tools/WalletTool.java
+++ b/tools/src/main/java/com/google/bitcoin/tools/WalletTool.java
@@ -19,6 +19,8 @@ package com.google.bitcoin.tools;
 
 import com.google.bitcoin.core.*;
 import com.google.bitcoin.crypto.KeyCrypterException;
+import com.google.bitcoin.crypto.MnemonicCode;
+import com.google.bitcoin.crypto.MnemonicException;
 import com.google.bitcoin.net.discovery.DnsDiscovery;
 import com.google.bitcoin.params.MainNetParams;
 import com.google.bitcoin.params.RegTestParams;
@@ -30,7 +32,9 @@ import com.google.bitcoin.store.*;
 import com.google.bitcoin.uri.BitcoinURI;
 import com.google.bitcoin.uri.BitcoinURIParseException;
 import com.google.bitcoin.utils.BriefLogFormatter;
+import com.google.bitcoin.wallet.DeterministicSeed;
 import com.google.common.base.Charsets;
+import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableList;
 import com.google.common.io.Resources;
 import com.google.common.util.concurrent.ListenableFuture;
@@ -67,12 +71,13 @@ import java.util.logging.LogManager;
 public class WalletTool {
     private static final Logger log = LoggerFactory.getLogger(WalletTool.class);
 
+    private static OptionSet options;
     private static OptionSpec<Date> dateFlag;
     private static OptionSpec<Integer> unixtimeFlag;
+    private static OptionSpec<String> seedFlag;
 
     private static NetworkParameters params;
     private static File walletFile;
-    private static OptionSet options;
     private static BlockStore store;
     private static AbstractBlockChain chain;
     private static PeerGroup peers;
@@ -176,23 +181,13 @@ public class WalletTool {
         parser.accepts("help");
         parser.accepts("force");
         parser.accepts("debuglog");
-        OptionSpec<String> walletFileName = parser.accepts("wallet")
-                .withRequiredArg()
-                .defaultsTo("wallet");
-        OptionSpec<NetworkEnum> netFlag = parser.accepts("net")
-                .withOptionalArg()
-                .ofType(NetworkEnum.class)
-                .defaultsTo(NetworkEnum.PROD);
-        dateFlag = parser.accepts("date")
-                .withRequiredArg()
-                .ofType(Date.class)
+        OptionSpec<String> walletFileName = parser.accepts("wallet").withRequiredArg().defaultsTo("wallet");
+        seedFlag = parser.accepts("seed").withRequiredArg();
+        OptionSpec<NetworkEnum> netFlag = parser.accepts("net").withOptionalArg().ofType(NetworkEnum.class).defaultsTo(NetworkEnum.PROD);
+        dateFlag = parser.accepts("date").withRequiredArg().ofType(Date.class)
                 .withValuesConvertedBy(DateConverter.datePattern("yyyy/MM/dd"));
-        OptionSpec<WaitForEnum> waitForFlag = parser.accepts("waitfor")
-                .withRequiredArg()
-                .ofType(WaitForEnum.class);
-        OptionSpec<ValidationMode> modeFlag = parser.accepts("mode")
-                .withRequiredArg()
-                .ofType(ValidationMode.class)
+        OptionSpec<WaitForEnum> waitForFlag = parser.accepts("waitfor").withRequiredArg().ofType(WaitForEnum.class);
+        OptionSpec<ValidationMode> modeFlag = parser.accepts("mode").withRequiredArg().ofType(ValidationMode.class)
                 .defaultsTo(ValidationMode.SPV);
         OptionSpec<String> chainFlag = parser.accepts("chain").withRequiredArg();
         // For addkey/delkey.
@@ -798,7 +793,40 @@ public class WalletTool {
             System.err.println("Wallet creation requested but " + walletFile + " already exists, use --force");
             return;
         }
-        wallet = new Wallet(params);
+        if (options.has(seedFlag)) {
+            long creationTimeSecs = MnemonicCode.BIP39_STANDARDISATION_TIME_SECS;
+            if (options.has(dateFlag))
+                creationTimeSecs = options.valueOf(dateFlag).getTime() / 1000;
+            String seedStr = options.valueOf(seedFlag);
+            DeterministicSeed seed;
+            if (seedStr.contains(" ")) {
+                // Parse as mnemonic code.
+                final List<String> split = ImmutableList.copyOf(Splitter.on(" ").omitEmptyStrings().split(seedStr));
+                try {
+                    seed = new DeterministicSeed(split, creationTimeSecs);
+                } catch (MnemonicException.MnemonicLengthException e) {
+                    System.err.println("The seed did not have 12 words in, perhaps you need quotes around it?");
+                    return;
+                } catch (MnemonicException.MnemonicWordException e) {
+                    System.err.println("The seed contained an unrecognised word: " + e.badWord);
+                    return;
+                } catch (MnemonicException.MnemonicChecksumException e) {
+                    System.err.println("The seed did not pass checksumming, perhaps one of the words is wrong?");
+                    return;
+                }
+            } else {
+                // Parse as hex or base58
+                byte[] bits = Utils.parseAsHexOrBase58(seedStr);
+                if (bits.length != 16) {
+                    System.err.println("The given hex/base58 string is not 16 bytes");
+                    return;
+                }
+                seed = new DeterministicSeed(bits, creationTimeSecs);
+            }
+            wallet = Wallet.fromSeed(params, seed);
+        } else {
+            wallet = new Wallet(params);
+        }
         if (password != null)
             wallet.encrypt(password);
         wallet.saveToFile(walletFile);