Background: Cognitive efficiency is crucial for many areas of human activity. It affects the employees’ efficiency and safety at the workplace. An important element of the prevention of accidents at work is the appropriate professional selection, which consists in checking the characteristics of candidates needed for a given position, and for this purpose, a psychological diagnosis is carried out. The aim of the study was to develop tools for cognitive diagnosis that are characterized by good psychometric properties. Material and Methods: Tools for the diagnosis of simple reaction time (Abili-time), choice reaction time (Abili-select), prolonged attention (Abili-space, Abili-digit), and working memory (Abili-langmem, Abili-mathmem) were developed. Validation studies were conducted with 221 individuals aged 20–60 to assess relevance and reliability (internal consistency and temporal stability), and with the participation of 61 in a retest 3 months after the first measurement. Paper tests (CTT, TUS, Digit Span from WAIS-R(PL)) and tests from the Vienna test system (RT, SIGNAL, CORSI, ALS) were used to assess validity. Results: The analysis showed that the Abili-time and Abili-select tests have satisfactory internal consistency. Analysis of temporal stability showed significant test-retest correlations for Abili-select, Abili-space, Abili-digit and Abili-langmem. Abili-time had slightly lower temporal stability. The temporal stability of Abili-mathmem was not confirmed. Significant correlations were obtained between the results of the developed tools with measures measuring similar constructs. Conclusions: The conducted research confirms the validity and reliability of Abili-time, Abili-select and Abili-space. Further work is needed on working memory tests, which are noteworthy due to the lack of other tools available on the market to test these functions. Further research should involve more people as well as carrying out standardization work. Med Pr. 2023;74(2):103–18