diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index e7b1f7b..263814c 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -59,10 +59,10 @@
 #define CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE       20000 //size of block (bytes) after which reward for block calculated using block size
 #define CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE          600
 #define CRYPTONOTE_DISPLAY_DECIMAL_POINT                12
-// COIN - number of smallest units in one coin
-#define COIN                                            ((uint64_t)100000000) // pow(10, 8)
-#define DEFAULT_FEE                                     ((uint64_t)1000000) // pow(10, 6)
-
+// COIN - number of smallest units in one coin (currently unused except by tests)
+#define COIN                                            ((uint64_t)1000000000000) // pow(10, 12)
+#define DEFAULT_FEE                                     ((uint64_t)10000000000) // pow(10, 10)
+#define MINIMUM_RELAY_FEE                               ((uint64_t)1000000) // pow(10, 6)
 
 #define ORPHANED_BLOCKS_MAX_COUNT                       100
 
diff --git a/src/cryptonote_core/tx_pool.cpp b/src/cryptonote_core/tx_pool.cpp
index 6f67464..e7acae0 100644
--- a/src/cryptonote_core/tx_pool.cpp
+++ b/src/cryptonote_core/tx_pool.cpp
@@ -86,7 +86,7 @@ namespace cryptonote
     }
 
     uint64_t fee = inputs_amount - outputs_amount;
-    if (!kept_by_block && fee < DEFAULT_FEE)
+    if (!kept_by_block && fee < MINIMUM_RELAY_FEE)
     {
       LOG_ERROR("transaction fee is not enough: " << print_money(fee) << ", minumim fee: " << print_money(DEFAULT_FEE));
       tvc.m_verifivation_failed = true;
@@ -449,9 +449,13 @@ namespace cryptonote
       if (total_size > median_size)
         break;      
 
+      // Don't mine transactions with too-low fee
+      if (DEFAULT_FEE > MINIMUM_RELAY_FEE && tx.second.fee < DEFAULT_FEE)
+	continue;
+
       // Skip transactions that are not ready to be
       // included into the blockchain or that are
-      // missing key images
+      // double spends of another transaction already in the template
       if (!is_transaction_ready_to_go(tx.second) || have_key_images(k_images, tx.second.tx))
         continue;