Body weight change was monitored in 73 hospitalized depressed patients treated with one of four antidepressants for 1 month. After a 2-week medication-free period, patients were randomly assigned to treatment with amitriptyline, nortriptyline, desipramine, or zimelidine. By the end of 1 month, treatment with all three tricyclic compounds promoted weight gain, with the greatest increase observed during amitriptyline treatment; less weight was gained by patients treated with nortriptyline and desipramine. In contrast, most patients treated with zimelidine showed no weight gain and, in many cases, demonstrated weight loss. Weight change during treatment was not associated with age, sex, severity of depression, obesity, weight loss during depression, or clinical response.