diff --git a/01-Find-Missing-Number-in-a-sorted-array.py b/01-Find-Missing-Number-in-a-sorted-array.py
new file mode 100644
index 00000000..ea8495f2
--- /dev/null
+++ b/01-Find-Missing-Number-in-a-sorted-array.py
@@ -0,0 +1,21 @@
+def missingNumber(arr):
+    n = len(arr)
+    
+    # Extreme cases
+    if arr[0] != 1:
+        return 1
+    if arr[n - 1] != n + 1:
+        return n + 1
+        
+    # Implementing binary search
+    lo, hi = 0, n - 1
+    while hi - lo > 1:
+        mid = (lo + hi) // 2
+        if arr[lo] - lo != arr[mid] - mid:
+            hi = mid
+        elif arr[hi] - hi != arr[mid] - mid:
+            lo = mid
+    return arr[lo] + 1
+
+arr = [1, 2, 3, 4, 6, 7, 8]
+print(missingNumber(arr))
\ No newline at end of file