diff --git a/src/Assembleur.cpp b/src/Assembleur.cpp
index d99c11e..17ce3fd 100644
--- a/src/Assembleur.cpp
+++ b/src/Assembleur.cpp
@@ -1,5 +1,6 @@
 #include "Assembleur.h"
 
+#include <algorithm>
 #include <map>
 #include <sstream>
 #include <stdexcept>
@@ -122,6 +123,9 @@ std::uint32_t Assembleur::ParseInstruction(const std::string& a_Str, std::uint32
 	std::string ins;
 	ss >> ins;
 
+	// to lower case
+	std::transform(ins.begin(), ins.end(), ins.begin(), [](unsigned char c) { return std::tolower(c); });
+
 	auto it = INSTRUCTION_KEYS.find(ins);
 	if (it == INSTRUCTION_KEYS.end()) {
 		throw std::invalid_argument("[Line " + std::to_string(a_RealLine) + "] " + "Instruction \"" + ins + "\" not found !");