The aim of this research was to evaluate the effects of a resistance training protocol on iron metabolism of police working dogs. Understanding of how physical exercise influences biochemical parameters is essential for a proper interpretation of exams and adjustments of nutritional and conditioning programs. Nine dogs, being four Belgian Malinois and five German Shepherd, 18.56±0.53 months old, were evaluated before (M1) and six weeks after (M2) a training program using a treadmill. Training sessions were performed twice/week including a 20-min of treadmill activity on a speed compatible with 60-80% of HRpeak on weeks 1 and 2; same exercise of weeks 1 and 2 with a 5% grade added between 7.5 and 12.5 min on weeks 3 and 4; and, same protocol of weeks 3 and 4 with three short bursts of strenuous exercise 60 min after the end of the treadmill exercise on weeks 5 and 6. On both moments (M1 and M2), animals were examined and blood samples were obtained before (T0) and after (T1) an incremental effort test and at 30 min (T2) and 120 min (T3) of recovery. Serum iron (Fe), total iron-binding capacity (TIBC) and transferrin saturation (TS) were determined. All variables were analysed using Tukey test, with P<0.05. Iron parameters were not modified by the current exercise protocol for training police working dogs.