We examined item nonresponse in questionnaires that assessed the physical functioning, emotional status, and satisfaction with care of surgical patients recently discharged from the hospital following coronary artery bypass graft surgery (CABG; N = 267), total hip replacement (THR; N = 283), and transurethral prostatectomy (TURP; N = 292). For all conditions, the total number of missing responses did not vary with age. More functional and healthier CABG and THR patients generated fewer missing responses than less healthy patients, whereas less educated TURP patients responded to items less frequently than more educated patients. The correlates of specific item nonresponse varied across samples. Most often, perceived health status, assistance with completion of the questionnaire, and patient-reported confusion all related to whether or not specific items were missing. The influence of these variables, however, varied by surgical condition. These results indicate that a proportion of elderly and sick respondents may not respond to at least some items, but it is possible to achieve a high level of data completeness if multiple item scales are used and questions are carefully designed to be salient to the population studied.