diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7dab9d6..e0beb93 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,7 @@ pkg_check_modules(JACK jack>=0.118)
 SET(SOURCES
 	client.cpp
 	client.h
+	cvbase.cpp
 	cvbase.h
 	cvin.cpp
 	cvin.h
diff --git a/cvbase.cpp b/cvbase.cpp
new file mode 100644
index 0000000..26a0028
--- /dev/null
+++ b/cvbase.cpp
@@ -0,0 +1,12 @@
+#include <cstring>
+#include "cvbase.h"
+
+bool CVBase::find(const char *name) const
+{
+	MappingList::const_iterator it;
+	for (it = m_mapping_list.begin(); it != m_mapping_list.end(); ++it) {
+		const Mapping *m = &(*it);
+		if (!strcmp(m->name.c_str(), name)) return true;
+	}
+	return false;
+}
diff --git a/cvbase.h b/cvbase.h
index 63dd759..95ba9f3 100644
--- a/cvbase.h
+++ b/cvbase.h
@@ -22,6 +22,8 @@ public:
 		m_mapping_list.push_back(m);
 	}
 
+	bool find(const char *name) const;
+
 	void stop()
 	{
 		close();
diff --git a/jm2cv.cpp b/jm2cv.cpp
index 4facbf8..cfb66aa 100644
--- a/jm2cv.cpp
+++ b/jm2cv.cpp
@@ -89,12 +89,20 @@ bool read_config(const char *filename)
 					std::clog << line << ": MIDI channel " << channel << " must be between -1 and 15." << std::endl;
 					continue;
 				}
+				if (cvout.find(name)) {
+					std::clog << line << ": Name '" << name << "' already defined." << std::endl;
+					continue;
+				}
 				cvout.add_mapping(Mapping(name, channel, itype, ccmsb, cclsb, mrl, mru, crl, cru, latency, has_lsb));
 			} else if (!strcmp(dir, "cvin")) {
 				if (channel < 0 || channel > 15) {
 					std::clog << line << ": MIDI channel " << channel << " must be between 0 and 15." << std::endl;
 					continue;
 				}
+				if (cvin.find(name)) {
+					std::clog << line << ": Name '" << name << "' already defined." << std::endl;
+					continue;
+				}
 				cvin.add_mapping(Mapping(name, channel, itype, ccmsb, cclsb, mrl, mru, crl, cru, latency, has_lsb));
 			}
 		}