diff --git a/CHANGELOG b/CHANGELOG
index de5b1dd72..70b5b0aa3 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -34,6 +34,13 @@ o Fixed a traceroute bug related to tracing between interfaces of a
   multi-homed host.  Thanks to David Fifield for reporting the problem
   and Eddie Bell for the fix.
 
+o Service detection (-sV) is now disabled when used with the IPProto Scan
+  (-sO).  Nmap would try to run the Service Scan after the IPProto Scan,
+  which would cause it to fail without outputting the protocol information,
+  or performing any other tasks (like Traceroute).  The Service Detection
+  line informing you where to send incorrect results is no longer outputted
+  when using the Service Scan with the Ping Scan (-sP) either. [Kris]
+
 o Updated IANA assignment IP list for random IP (-iR) generation. [Kris]
 
 4.21ALPHA4
diff --git a/NmapOps.cc b/NmapOps.cc
index dbf84c27d..36bf3f9a1 100644
--- a/NmapOps.cc
+++ b/NmapOps.cc
@@ -437,6 +437,14 @@ void NmapOps::ValidateOptions() {
     fatal("WARNING:  OS Scan is unreliable with a ping scan.  You need to use a scan type along with it, such as -sS, -sT, -sF, etc instead of -sP");
   }
 
+  if (servicescan && ipprotscan) {
+    error("WARNING: Disabling Service Scan (-sV) as it is incompatible with the IPProto Scan (-sO)");
+    servicescan = 0;
+  }
+
+  if (servicescan && pingscan)
+    servicescan = 0;
+
   if (defeat_rst_ratelimit && !synscan) {
       fatal("Option --defeat-rst-ratelimit works only with a SYN scan (-sS)");
   }