The aim of the study was to calculate the magnitudes of moments of force acting about the bilateral hip and knee joint axes during ergometer cycling. Six healthy subjects pedalled a weight-braked bicycle ergometer at different workloads, pedalling rates, saddle heights and pedal foot position. During cycling at 120 Watts, 60 revolutions per minute with mid-saddle height and anterior pedal foot position, the mean peak flexing and extending hip load moments were 34.3 and 8.9 Nm, respectively. Mean peak flexing knee load moments was 28.8 Nm and extending moment was 11.9 Nm. Hip load moments were significantly increased by increasing the ergometer workload or pedalling rate. For knee load moments, workload was the most important factor. The flexing knee load moment did not change with changes in pedalling rate. Different saddle heights or pedal food positions had a slight but not always statistically significant influence on the hip and knee joint loads. The maximum hip and knee joint load moments induced during cycling were small compared with those obtained during other exercises or normal activities such as level walking, stair climbing, and lifting.