diff --git a/src/core/World.cpp b/src/core/World.cpp
index 625ccf57..c884f1ed 100644
--- a/src/core/World.cpp
+++ b/src/core/World.cpp
@@ -382,7 +382,7 @@ CWorld::ProcessVerticalLine(const CVector &point1, float z2, CColPoint &point, C
 {
 	AdvanceCurrentScanCode();
 	CVector point2(point1.x, point1.y, z2);
-	return ProcessVerticalLineSector(*GetSector(GetSectorIndexX(point1.x), GetSectorIndexX(point1.y)),
+	return ProcessVerticalLineSector(*GetSector(GetSectorIndexX(point1.x), GetSectorIndexY(point1.y)),
 	                                 CColLine(point1, point2), point, entity, checkBuildings, checkVehicles,
 	                                 checkPeds, checkObjects, checkDummies, ignoreSeeThrough, poly);
 }