Background & objectives:: Detection of prodromal symptoms among patients with mania by their immediate relatives has been seldom examined. We carried out this study to examine the ability to detect and report prodromol symptoms of manic relapses by patients themselves and their relatives. Methods:: The ability of patients and their relatives to detect prodromal symptoms was examined among 60 remitted patients, 30 each with DSM-IV diagnoses of bipolar disorder and recurrent depressive disorder, with recent manic/depressive relapses, and their 60 immediate relatives, using an instrument composed of items from common symptom-scales, as well as by unstructured interview. Results:: Seventy per cent of patients with mania reported prodromes prior to relapse. This was significantly (P<0.01) less than the proportion of their relatives (97%), as well as the proportion of patients with unipolar depression (93%), reporting prodromal symptoms (P<0.05) among patients. Mean duration of the prodromal period reported by patients with mania was about 20 days (median-10 days); relatives reported durations which were longer by about 5 days. Prodromes of unipolar depression (mean 42.7 days; median- 21 days), were significantly longer than of mania, when reported by patients, but not by their relatives. Differences in reporting of prodromes, between relatives and patients seen in mania, were not observed in unipolar depression. The number and type of prodromal symptoms of mania reported was similar among patients and relatives. Interpretation & conclusions:: Our findings showed that relatives of patients with mania were better at detecting prodromes of relapse; thus, input from relatives can improve the early detection of prodromal symptoms to prevent relapses of bipolar disorder.