| Waldemar Blatskauskas | |
| Height Ft: | 6 |
| Height In: | 2.5 |
| Birth Date: | 17 March 1938 |
| Team1: | Regatas Campinas |
| Team2: | Tietê |
| Team3: | São Carlos Clube |
| Team4: | XV de Novembro de Piracicaba |
| Career Position: | Small forward / power forward |
Waldemar Blatskauskas, also known simply as Waldemar (17 March 1938 – 6 March 1964) was a Brazilian professional basketball player.
During his pro career, Blatskauskas played with the Brazilian clubs Regatas Campinas, Tietê, São Carlos Clube, and XV de Novembro de Piracicaba.
Blatskauskas was a member of the senior Brazilian national basketball team that won gold medals at the 1959 FIBA World Championship, and the 1963 FIBA World Championship. With Brazil, he also won a bronze medal at the 1960 Summer Olympic Games. He also won the following medals: a bronze medal at the 1959 Pan American Games, a silver medal at the 1963 Pan American Games, gold medals at the 1958 FIBA South American Championship and the 1961 FIBA South American Championship, and a gold medal at the 1963 Summer Universiade.
Blatskauskas died in Brazil, in a traffic accident, on 6 March 1964.