diff --git a/BuildOptions.cmake b/BuildOptions.cmake
index 168bd5527d..b4f33736ab 100644
--- a/BuildOptions.cmake
+++ b/BuildOptions.cmake
@@ -27,9 +27,6 @@ set(DATADIR share/bro
 set(BROv6 false
     CACHE STRING "enable IPv6 processing" FORCE)
 
-set(USE_INT64 true
-    CACHE STRING "enable use of int64 (long long) for integers" FORCE)
-
 # TODO: add to configure wrapper as '--enable-debug'
 # TODO: make this option do stuff
 set(ENABLE_DEBUG false
diff --git a/config.h.in b/config.h.in
index e633e7f091..7d55d001b4 100644
--- a/config.h.in
+++ b/config.h.in
@@ -183,9 +183,6 @@
 /* GeoIP geographic lookup functionality */
 #undef USE_GEOIP
 
-/* enable use of 64-bit integers */
-#cmakedefine USE_INT64
-
 /* Use libclamav */
 #undef USE_LIBCLAMAV
 
diff --git a/src/BitTorrentTracker.cc b/src/BitTorrentTracker.cc
index be72a17d26..50f6d0449c 100644
--- a/src/BitTorrentTracker.cc
+++ b/src/BitTorrentTracker.cc
@@ -8,13 +8,8 @@
 #include <sys/types.h>
 #include <regex.h>
 
-#ifdef USE_INT64
 # define FMT_INT "%lld"
 # define FMT_UINT "%llu"
-#else
-# define FMT_INT "%d"
-# define FMT_UINT "%u"
-#endif
 
 static TableType* bt_tracker_headers = 0;
 static RecordType* bittorrent_peer;
diff --git a/src/Desc.cc b/src/Desc.cc
index 0a494bcd9c..baf3ad1160 100644
--- a/src/Desc.cc
+++ b/src/Desc.cc
@@ -105,7 +105,6 @@ void ODesc::Add(uint32 u)
 		}
 	}
 
-#ifdef USE_INT64
 void ODesc::Add(int64 i)
 	{
 	if ( IsBinary() )
@@ -129,7 +128,6 @@ void ODesc::Add(uint64 u)
 		Add(tmp);
 		}
 	}
-#endif
 
 void ODesc::Add(double d)
 	{
diff --git a/src/Desc.h b/src/Desc.h
index de09f12be4..49b331d51b 100644
--- a/src/Desc.h
+++ b/src/Desc.h
@@ -57,10 +57,8 @@ public:
 	void AddN(const char* s, int len)	{ AddBytes(s, len); }
 	void Add(int i);
 	void Add(uint32 u);
-#ifdef USE_INT64
 	void Add(int64 i);
 	void Add(uint64 u);
-#endif
 	void Add(double d);
 
 	// Add s as a counted string.
diff --git a/src/Hash.cc b/src/Hash.cc
index 47216a8d9d..ef8b2a61cf 100644
--- a/src/Hash.cc
+++ b/src/Hash.cc
@@ -237,8 +237,6 @@ HashKey::HashKey(bro_uint_t u)
 	is_our_dynamic = 0;
 	}
 
-#ifdef USE_INT64
-
 HashKey::HashKey(uint32 u)
 	{
 	key_u.u32 = u;
@@ -248,8 +246,6 @@ HashKey::HashKey(uint32 u)
 	is_our_dynamic = 0;
 	}
 
-#endif // USE_INT64
-
 HashKey::HashKey(const uint32 u[], int n)
 	{
 	size = n * sizeof(u[0]);
diff --git a/src/Hash.h b/src/Hash.h
index 5ed41b05e9..fa1f00f91f 100644
--- a/src/Hash.h
+++ b/src/Hash.h
@@ -24,9 +24,7 @@ class HashKey {
 public:
 	HashKey(bro_int_t i);
 	HashKey(bro_uint_t u);
-#ifdef USE_INT64
 	HashKey(uint32 u);
-#endif
 	HashKey(const uint32 u[], int n);
 	HashKey(double d);
 	HashKey(const void* p);
@@ -78,9 +76,7 @@ protected:
 
 	union {
 		bro_int_t i;
-#ifdef USE_INT64
 		uint32 u32;
-#endif
 		double d;
 		const void* p;
 	} key_u;
diff --git a/src/TCP_Endpoint.cc b/src/TCP_Endpoint.cc
index 826c7f5636..6cb52f1f03 100644
--- a/src/TCP_Endpoint.cc
+++ b/src/TCP_Endpoint.cc
@@ -161,8 +161,6 @@ bro_int_t TCP_Endpoint::Size() const
 	{
 	bro_int_t size;
 
-#ifdef USE_INT64
-
 	uint64 last_seq_64 = (uint64(last_seq_high) << 32) | last_seq;
 	uint64 ack_seq_64 = (uint64(ack_seq_high) << 32) | ack_seq;
 	if ( last_seq_64 > ack_seq_64 )
@@ -170,26 +168,6 @@ bro_int_t TCP_Endpoint::Size() const
 	else
 		size = ack_seq_64 - start_seq;
 
-#else
-
-	if ( seq_delta(last_seq, ack_seq) > 0 || ack_seq == start_seq + 1 )
-		// Either last_seq corresponds to more data sent than we've
-		// seen ack'd, or we haven't seen any data ack'd (in which
-		// case we should trust last_seq anyway).  This last test
-		// matters for the case in which the connection has
-		// transferred > 2 GB of data, in which case we will find
-		// seq_delta(last_seq, ack_seq) < 0 even if ack_seq
-		// corresponds to no data transferred.
-		size = last_seq - start_seq;
-
-	else
-		// It could be that ack_seq > last_seq, if we've seen an
-		// ack for the connection (say in a FIN) without seeing
-		// the corresponding data.
-		size = ack_seq - start_seq;
-
-#endif
-
 	// Don't include SYN octet in sequence space.  For partial connections
 	// (no SYN seen), we're still careful to adjust start_seq as though
 	// there was an initial SYN octet, because if we don't then the
diff --git a/src/Val.h b/src/Val.h
index 925015c9c1..5a2faee9d7 100644
--- a/src/Val.h
+++ b/src/Val.h
@@ -127,7 +127,6 @@ public:
 #endif
 		}
 
-#ifdef USE_INT64
 	Val(int64 i, TypeTag t)
 		{
 		val.int_val = i;
@@ -147,7 +146,6 @@ public:
 		bound_id = 0;
 #endif
 		}
-#endif // USE_INT64
 
 	Val(double d, TypeTag t)
 		{
diff --git a/src/bro.bif b/src/bro.bif
index a4111bb041..8dace1247d 100644
--- a/src/bro.bif
+++ b/src/bro.bif
@@ -222,25 +222,15 @@ static void do_fmt(const char*& fmt, Val* v, ODesc* d)
 					u = ntohl(uint32(u));
 				}
 
-#ifdef USE_INT64
 			snprintf(fmt_buf, sizeof(fmt_buf), "%%%s%s", num_fmt,
 					*fmt == 'd' ? "llu" : "llx");
-#else
-			snprintf(fmt_buf, sizeof(fmt_buf), "%%%s%c", num_fmt,
-					*fmt == 'd' ? 'u' : 'x');
-#endif
 			snprintf(out_buf, sizeof(out_buf), fmt_buf, u);
 			}
 
 		else
 			{
-#ifdef USE_INT64
 			snprintf(fmt_buf, sizeof(fmt_buf), "%%%s%s", num_fmt,
 					*fmt == 'd' ? "lld" : "llx");
-#else
-			snprintf(fmt_buf, sizeof(fmt_buf), "%%%s%c", num_fmt,
-					*fmt == 'd' ? 'd' : 'x');
-#endif
 			snprintf(out_buf, sizeof(out_buf), fmt_buf,
 					v->CoerceToInt());
 			}
diff --git a/src/util.h b/src/util.h
index 96aeb761e1..f4f007a27d 100644
--- a/src/util.h
+++ b/src/util.h
@@ -44,15 +44,8 @@ typedef unsigned int uint32;
 typedef unsigned short uint16;
 typedef unsigned char uint8;
 typedef long long int int64;
-
-#ifdef USE_INT64
-	typedef int64 bro_int_t;
-	typedef uint64 bro_uint_t;
-#else
-	typedef int bro_int_t;
-	typedef uint32 bro_uint_t;
-// #	error "USE_INT64 not defined!"
-#endif
+typedef int64 bro_int_t;
+typedef uint64 bro_uint_t;
 
 #if SIZEOF_LONG_LONG == 8
 typedef unsigned long long uint64;