diff --git a/medium/maximum_matrix_sum.py b/medium/maximum_matrix_sum.py
new file mode 100644
index 0000000..bcb2b3e
--- /dev/null
+++ b/medium/maximum_matrix_sum.py
@@ -0,0 +1,20 @@
+#  https://leetcode.com/problems/maximum-matrix-sum
+from typing import List
+
+class Solution:
+    def maxMatrixSum(self, matrix: List[List[int]]) -> int:
+        total = 0
+        negative_count = 0
+        min_val = float("inf")
+        length = len(matrix)
+        for i in range(length):
+            for j in range(length):
+                if matrix[i][j] < 0:
+                    total += -matrix[i][j]
+                    negative_count += 1
+                else:
+                    total += matrix[i][j]
+                min_val = min(min_val, abs(matrix[i][j]))
+        if negative_count % 2 != 0:
+            total -= 2 * int(min_val)
+        return total