During the First World War, all battalions of the Non-Active Permanent Militia were renumbered as part of the Canadian Expeditionary Force. The 48th supplied three battalions - the 15th, 92nd and 134th and Old Boys serving with those units have been identified below. 

• ANGUS, Captain William Glen, MC (SAC 1937-1938)
• BARCLAY, Lieutenant W. C. (SAC 1902-1906) 15th Battalion and WWII
• BATH, Lieutenant E. O. (SAC 1905-1907) 15th Battalion, Gassed, POW
• BEST, Lieutenant Alan R.  (SAC 1985-1992)
• BROWN, Captain J. L. (SAC 1918-1927)
• BROWN, Private K. (SAC 1936-1938)
• BROWN, Captain R. A. (SAC 1908-1914) 15th Battalion 
• BURNS, Private Gavin K. (SAC 1913-1914)
• COUSINS, Lieutenant D. F. (SAC 1926-1932)
• COX, Major H. M. (SAC 1931-1934)
• CRAWFORD, Major S. H. (SAC 1906-1911)
• DICKIE, Lieutenant David Munn (SAC 1933-1937)
• DICKIE, Corporal Peter M. (SAC 1939-1940)
• DONALD, Captain H. H. (SAC 1902-1907) 15th Battalion
• FEE, Private E. S. (SAC 1930-1933)
• GANONG, Lieutenant Colonel (Acting Brigadier) James Edwin, ED, MiD (SAC 1913-1914)
• GRAHAM, Lieutenant R. L. (SAC 1936-1941)
• HANNA, Captain W. B. (SAC 1903-1911) 92nd Battalion
• HARRIS, Major R.J. (SAC 1931-1933)
• HUNTER, Private D.C. (SAC 1936-1941)
• KAY, Major John, MC (SAC 1901-1909) 15th Battalion
• KING, Lieutenant Colonel Bruce B. (SAC 1911-1921)
• LOUDON, Lieutenant Brian Melville (SAC 1902-1906)
• LOUGH, Captain C.D. (SAC 1924-1929)
• LOWNDES, Colonel, John M (SAC 1939-1944)
• MACDONALD, Captain F. W. (SAC 1900-1908) 15th Battalion
• MACEACHREN, Honorary Colonel Frank F. CVO, CM, KStJ, ED, CD, ADC (SAC 1931-1937)
• MACLAREN, Captain K. B. (SAC 1903-1907)
• MALONE, Lieutenant Maurice E. (SAC 1907-1913) 15th Battalion 
• MATHEWS, Lieutenant Jan (SAC 1989-1996) 
• MACFARLANE, Stan (Master 1947-1982) 
• MCKENZIE, Sergeant William A. (SAC 1940-1943)
• MCLEOD, Sergeant Jim B. (SAC 1939-1943)
• MUNRO, Lieutenant William McClain (SAC 1907-1910) 
• NEWMAN, Lieutenant M. F. (SAC 1904-1908)
• PENTLAND, Lieutenant W. T. Paul (SAC 1929-1937)
• PHIBBS, Captain G. O. G. (SAC 1936-1937)
• RAMSEY, Lieutenant Colonel Alan R. (SAC 1902-1908, Master 1921-1926, 1947-1960)
• READ, Honorary Lieutenant Colonel Richard, CD (SAC '50)
• REID, Lieutenant Colonel John (SAC )
• ROLPH, Captain G. G. (SAC 1915-1928)
• SLATTER, Lieutenant A.M. (SAC 1901-1903)
• SMITH, Private J. R. (SAC 1906-1910) 15th Battalion
• SMITH, Lance Corporal K. S. (SAC 1927-1929)
• SNOW, Lieutenant Geoffrey A. (SAC 1907-1912) 134th Battalion 
• SNOW, Lieutenant G. B. (SAC 1906-1909) 134th Battalion
• TAYLOR, Lieutenant John C.  (SAC '52)
• URQUHART, Lieutenant A. (SAC 1912-1914) 15th Battalion, Trench Mortar Battery
• WEBBER, Lieutenant R. S. C. (SAC 1903-1911) 15th Battalion
• WILSON, Private A. C. H. (SAC 1911-1913)