3 May 1934
Marcel Thil beats Gustave Roth via majority decision 15/15
Middleweight (160 lb)
1 Sep 1936
Gustave Roth beats Heinz Lazek via points decision 15/15
Light Heavyweight (175 lb)
Gustave Roth becomes the IBU Light Heavyweight world champion
29 Oct 1936
Gustave Roth beats Adolf Witt via points decision 15/15
12 Jan 1937
Gustave Roth and Antonio Rodrigues share a draw 15/15
24 Mar 1937
Gustave Roth beats Merlo Preciso via points decision 15/15
1 May 1937
Gustave Roth beats John Andersson via points decision 15/15
1 Dec 1937
Gustave Roth and Karel Sys share a draw 15/15
21 Jan 1938
Gustave Roth beats Jupp Besselmann via points decision 15/15
25 Mar 1938
Adolf Heuser beats Gustave Roth via knockout 7/15