diff --git a/src/httpserver.cpp b/src/httpserver.cpp
--- a/src/httpserver.cpp
+++ b/src/httpserver.cpp
@@ -6,6 +6,7 @@
 
 #include "chainparamsbase.h"
 #include "compat.h"
+#include "config.h"
 #include "netbase.h"
 #include "rpc/protocol.h" // For HTTP status codes
 #include "sync.h"
@@ -39,6 +40,12 @@
 /** Maximum size of http request (request line + headers) */
 static const size_t MAX_HEADERS_SIZE = 8192;
 
+/**
+ * Maximum HTTP post body size. Twice the maximum block size is added to this
+ * value in practice.
+ */
+static const size_t MIN_SUPPORTED_BODY_SIZE = 0x02000000;
+
 /** HTTP request work item */
 class HTTPWorkItem final : public HTTPClosure {
 public:
@@ -56,7 +63,8 @@
     Config *config;
 };
 
-/** Simple work queue for distributing work over multiple threads.
+/**
+ * Simple work queue for distributing work over multiple threads.
  * Work items are simply callable objects.
  */
 template <typename WorkItem> class WorkQueue {
@@ -416,7 +424,8 @@
     evhttp_set_timeout(
         http, gArgs.GetArg("-rpcservertimeout", DEFAULT_HTTP_SERVER_TIMEOUT));
     evhttp_set_max_headers_size(http, MAX_HEADERS_SIZE);
-    evhttp_set_max_body_size(http, MAX_SIZE);
+    evhttp_set_max_body_size(
+        http, MIN_SUPPORTED_BODY_SIZE + 2 * config.GetMaxBlockSize());
     evhttp_set_gencb(http, http_request_cb, &config);
 
     if (!HTTPBindAddresses(http)) {
diff --git a/test/functional/abc-p2p-fullblocktest.py b/test/functional/abc-p2p-fullblocktest.py
--- a/test/functional/abc-p2p-fullblocktest.py
+++ b/test/functional/abc-p2p-fullblocktest.py
@@ -426,6 +426,11 @@
         update_block(32, [spend_p2sh_tx(max_p2sh_sigops)])
         yield accepted()
 
+        # Submit a very large block via RPC
+        large_block = block(
+            33, spend=out[24], block_size=self.excessive_block_size)
+        node.submitblock(ToHex(large_block))
+
 
 if __name__ == '__main__':
     FullBlockTest().main()