Previous investigations into peak cardiac power output (CPO peak) have been limited to clinical populations and healthy, but non-athletic adults, and normative data on trained individuals would allow a greater understanding of this parameter. Therefore, we recruited eight healthy, well-trained male cyclists. Peak oxygen consumption ((.)VO₂ peak) was assessed using an incremental ergometer test, and following a 40-min recovery period, peak cardiac output ((.)QT peak) was measured during a constant load test that elicited (.)VO₂ peak (±5%) using the Defares CO₂ rebreathing technique. CPO peak was calculated as described by Cooke et al. (1998). Mean (±SD) values during the constant load test were: (.)VO₂ peak, 4.94 ± 0.41 l min⁻¹; (.)QT peak, 36.5 ± 3.7 l min⁻¹; mean arterial pressure, 123 ± 8 mmHg and CPO peak, 9.9 ± 1.0 W. These results demonstrate CPO peak in a well-trained population to be approximately twice those observed in healthy, but non-athletic adults. The current data provide useful information regarding the upper limits and possible 'trainability' of cardiac pumping capacity for sedentary and clinically compromised individuals.