This thesis deals with the relationship between Working Memory, Working Memory Span tasks and general factor g and Broad cognitive abilities. Measured constructs are introduced in the theoretical part, with their evolution, various methods of their measurement and studies investigating the relation between them. The empirical part of the research has been conducted to verify the relationship between Working Memory and general intelligence factor g. It has been done to reveal the relationship between Working Memory Span tasks and Broad cognitive abilities as well. The question concerning the influence of the use of strategy while performing the automatic version of Working Memory Span tasks has been investigated as well.