The effects of hospitalization on affective status were assessed by an original protocol in 214 consecutive elderly patients (mean age=78.3+/−5.0 years, range=70–92 years). Psychological decompensation was significantly related to length of stay (p<0.01) and drug use (p<0.05) and unaffected by sex, marital status, prior living place, diagnostic category. Affective status and functional status were directly correlated (p<0.0001), although in 51% of medical patients the affective status worsened or remained unchanged despite improved physical function. Improvement in affective status occurred more frequently in surgical patients (p<0.001) due to psychological improvement following surgery. Physicians providing medical and surgical care for geriatric patients must remain aware of the patients' emotional response to hospitalization and illness, given the accompanying risk for psychological decompensation.