The aim of the present study was to compare the highest heart rate (HR) of soccer players recorded during competition matches with the maximum HR (HR(max)) estimated from age and the highest HR recorded in effort tests within a single category (intracategory) and between categories (intercategories).The sample was made up of 19 under-17 athletes, 12 under-20 athletes and 14 professional athletes of a Brazilian first division soccer team. Players' HR was monitored during official competition matches and maximum effort test with a set of HR monitors. The highest HR recorded during competitive matches (MHR1) was considered as the highest HR value attained by each player during matches. HR(max) estimated from age (MHR2) was estimated by using the equation HR(max)= (220-age). The highest HR recorded in effort tests (MHR3) was determined as being the highest HR value recorded during a maximum effort test (1 000-m run). The Wilcoxon test was used in intracategory statistical analysis. The Kruskal Wallis test was used in intercategory statistical analysis. The significance level adopted was P<0.05.In all categories, MHR3 was lower than MHR1. Concerning intercategory analysis, the three categories did not exhibit a difference in MHR1Relative to MHR3, the under-17 and under-20 categories were not different from each other. These two categories exhibited larger MHR3 values than the professional one did.HR(max) measured during field tests can be underestimated in relation to that measured during competition activities, maybe because the tests represent an artificial situation for athletes, who do not feel as motivated as during competitions.