It initially consisted of the part of the borough of Scarborough west of a line formed by Midland Avenue the Canadian National Railway line and Brimley Road and south of Eglinton Avenue. It also included the part of the city west of Birchmount Road and south of Lawrence Avenue East.
In 1976, it was redefined to consist of the part of the Borough of Scarborough south Eglinton Avenue East and west of Bellamy Road South, and the part south of Kingston Road and east of Bellamy Ravine Creek.
In 1987, it was redefined to consist of the part of the City of Scarborough south Eglinton Avenue East and west of Markham Road.
The electoral district was abolished in 1996 when it was redistributed when almost all of the riding was transferred to Scarborough Southwest riding.
A new riding named Scarborough Southwest was created out of Scarborough West and a small part of Scarborough East in 1996. It consisted initially of the part of the City of Scarborough lying south and west of a line drawn from the western city limit east along Eglinton Avenue East, north along Markham Road, east along the Canadian National Railway, southwest along Kingston Road, south along Scarborough Golf Club Road, southwest along Hill Crescent, southeast along Bellamy Ravine Creek.
All electoral information is taken from Elections Canada. Italicized expenditures from elections after 1997 refer to candidate submissions, and are presented when the final reviewed totals are not available. Expenditures from 1997 refer to submitted totals. The +/- figures from 1997 and 2004 are adjusted for redistribution.
Graph of election results in Scarborough Southwest (since 1968, minor parties that never got 2% of the vote or didn't run consistently are omitted)