diff --git a/src/ifcparse/IfcFile.h b/src/ifcparse/IfcFile.h
index daa31feb27..1e871412fe 100644
--- a/src/ifcparse/IfcFile.h
+++ b/src/ifcparse/IfcFile.h
@@ -39,6 +39,7 @@ public:
 	typedef boost::unordered_map<unsigned int, IfcUtil::IfcBaseClass*> entity_by_id_t;
 	typedef std::map<std::string, IfcSchema::IfcRoot*> entity_by_guid_t;
 	typedef std::map<unsigned int, std::vector<unsigned int> > entities_by_ref_t;
+	typedef std::map<unsigned int, IfcEntityList::ptr> ref_map_t;
 	typedef entity_by_id_t::const_iterator const_iterator;
 
 	class type_iterator : private entities_by_type_t::const_iterator {
@@ -77,6 +78,7 @@ private:
 	entities_by_type_t bytype;
 	entities_by_type_t bytype_excl;
 	entities_by_ref_t byref;
+	ref_map_t by_ref_cached_;
 	entity_by_guid_t byguid;
 	entity_entity_map_t entity_file_map;
 
diff --git a/src/ifcparse/IfcParse.cpp b/src/ifcparse/IfcParse.cpp
index 20d7cb53dd..cd904790af 100644
--- a/src/ifcparse/IfcParse.cpp
+++ b/src/ifcparse/IfcParse.cpp
@@ -1795,12 +1795,19 @@ IfcEntityList::ptr IfcFile::entitiesByReference(int t) {
 	entities_by_ref_t::const_iterator it = byref.find(t);
 	IfcEntityList::ptr ret;
 	if (it != byref.end()) {
-        ret.reset(new IfcEntityList);
-        ret->reserve((unsigned)it->second.size());
-		const std::vector<unsigned>& ids = it->second;
-		for (std::vector<unsigned>::const_iterator jt = ids.begin(); jt != ids.end(); ++jt) {
-			ret->push(entityById(*jt));
-		}
+        ref_map_t::const_iterator cached_it = by_ref_cached_.find(t);
+        if (cached_it != by_ref_cached_.end()) {
+            ret = cached_it->second;
+        }
+        else {
+            ret.reset(new IfcEntityList);
+            ret->reserve((unsigned)it->second.size());
+            const std::vector<unsigned>& ids = it->second;
+            for (std::vector<unsigned>::const_iterator jt = ids.begin(); jt != ids.end(); ++jt) {
+                ret->push(entityById(*jt));
+            }
+            by_ref_cached_[t] = ret;
+        }
 	}
 	return ret;
 }