Scrotal circumference is one of the fertility indicators and can provide an idea of the reproduction potential of a bull. Scrotal circumference is correlated with many productive and reproductive traits of bulls and their offspring. Age at first calving (AFC) is routinely recorded and is often used to evaluate heifer fertility. It could provide the information to select dams to stay on the farm in subsequent calving based on their expected performance. The objective of this study was to estimate the genetic parameters of these two traits in most numerous breeds in the Czech Republic: Charolais (22.7 %), Aberdeen Angus (14.9 %), Beef Simmental (12.2 %), and Limousine (9.9 %). These breeds together form 60 % of the Czech beef cattle population. We used a database from the period 1996 – 2023. Genetic parameters were determined by a two-trait model using the AIREMLF90 program. The heritability coefficient of the SC ranged between 0.08 (Limousine) to 0.19 (Charolais). Heritabilities for AFC were the highest for Aberdeen Angus (0.19) and 0.15 for other breeds. Genetic correlations between SC and AFC ranged from -0.17 (Charolais) to -0.07 (Limousine).