The physiological workload (PW) involved in garbage collection was assessed in a probabilistic sample of 70 Rio de Janeiro city garbage collectors to determine the adequacy of Brazilian labor legislation regarding classification of work. PW was measured as energy expenditure (EE) and heart rate (HR) during total work time (TT) and actual time (AT) in garbage collection on 4 consecutive days. Median EE values were 288.4 and 319.1 kcal.h-1 during TT and AT, respectively, indicating moderately intense work according to Brazilian legislation. However, PW was considered heavy when work classifications based on individual response to work were used: 1) ratio of EE and resting metabolic rate was above 5.0, indicating heavy workload according to the WHO; 2) mean percentage of maximal EE was higher (36.2 and 41.1% for TT and AT, respectively) than the limit for garbage collection (30%) suggested as maximal for Dutch workers; and 3) percentage of maximal HR reserve was also higher than 30% (32.2 and 37.5% for TT and AT, respectively). These results indicate the need for a revision of the workload classification in the Brazilian legislation to take individual workers' characteristics into account.