Muscular strength, endurance and cardiovascular fitness were evaluated in a group of patients (n = 11) previously treated for small cell lung cancer (SCLC). All SCLC patients were in complete remission and were 6 weeks posttherapy. Their results were compared to an age- and sex-matched group of cardiac patients who had undergone coronary artery bypass surgery (cardiac) 6–8 weeks prior, and a group of age- and sex-matched healthy controls. All subjects participated in a symptom-limited, graded exercise test on a cycle ergometer to determine peak aerobic power (VO2). Muscular strength and endurance of the upper and lower extremity were also assessed, with use of an Isokinetic dynamometer. Compared with both the healthy subjects and the cardiac patients, the SCLC patients demonstrated a significantly lower exercise tolerance time, maximal power output, and peak VO2(p< 0.05). Isokinetic testing of the lower extremity revealed lower peak torque, average torque, and absolute work values for the SCLC patients. Upper body muscular endurance was also significantly reduced in the SCLC patients when compared with that for the healthy controls or the cardiac patients (p< 0.05). Current results suggest significantly diminished capacities in both the cardiorespiratory and muscular systems of SCLC patients who are 6 weeks posttherapy.