diff --git a/CHANGELOG b/CHANGELOG
index f85d8560..5e836ec1 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -119,7 +119,9 @@ HISTORY
 
   2007-04-17 Jonathan Larmour
   * pbuf.c: Use s32_t in pbuf_realloc(), as an s16_t can't reliably hold
-  the difference between two u16_t's.
+    the difference between two u16_t's.
+  * sockets.h: FD_SETSIZE needs to match number of sockets, which is
+    MEMP_NUM_NETCONN in sockets.c right now.
 
   2007-04-12 Jonathan Larmour
   * icmp.c: Reset IP header TTL in ICMP ECHO responses (bug #19580).
diff --git a/src/include/lwip/sockets.h b/src/include/lwip/sockets.h
index 79ea9cd5..782a405a 100644
--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -213,7 +213,8 @@ typedef struct ip_mreq {
 
 #ifndef FD_SET
   #undef  FD_SETSIZE
-  #define FD_SETSIZE    16
+  /* Make FD_SETSIZE match NUM_SOCKETS in socket.c */
+  #define FD_SETSIZE    MEMP_NUM_NETCONN
   #define FD_SET(n, p)  ((p)->fd_bits[(n)/8] |=  (1 << ((n) & 7)))
   #define FD_CLR(n, p)  ((p)->fd_bits[(n)/8] &= ~(1 << ((n) & 7)))
   #define FD_ISSET(n,p) ((p)->fd_bits[(n)/8] &   (1 << ((n) & 7)))