The purpose of this study was to develop an oxygen consumption (VO2) measurement for adult hemiplegic patients during an incremental exercise arm-cranking test. Fifty-five adult hemiplegic patients performed a three-stage arm-cranking exercise test while VO2 was measured. The control group consisted of thirteen healthy elderly persons who performed a similar arm-cranking test until exhaustion. The results indicated that there was a significant difference in VO2 during rest periods between the adult hemiplegic and control groups. Based on data analysis, we developed an equation to estimate the VO2 for adult hemiplegic patients: VO2(ml/min) = (kgm/min x 4.2 ml/kgm) + ((4.2 ml/kg/min x kg body weight) + 105.6 ml/min) (r = 0.847), while the equation for the controls was VO2(ml/min) = (kgm/min x 4.3 ml/kgm) + ((2.9 ml/kg/min x kg body weight) + 105.5 ml/min) (r = 0.932). There was no significant difference between the estimated VO2 for the new equations (nVO2) and the measured VO2 (mVO2) in the two groups at any stage. In our data analysis, based on an estimated VO2 from the American College of Sports Medicine (ACSM) equation (aVO2), the nVO2 and mVO2 at each stage showed lower aVO2 than either nVO2 or mVO2 in each subject (p < 0.05). These findings suggest that the ACSM equation is unlikely to be applicable for estimating VO2 for one hand arm-cranking exercise. In conclusion, the new equations established in this study, when used with a specific prescribed exercise testing protocol, would allow us to estimate VO2 more accurately for both adult hemiplegic patients and healthy elderly persons.