Objective - This study aims to improve the economic knowledge of major depression. It reports the investigation methodology and some preliminary indications on direct and indirect costs associated to this illness. Setting - Centro Psicosociale (CPS) USSL 72, Magenta (Mi) Italy. Design - We enrolled 10 patients (7F and 3M) with age between 34 and 65 (average 49.2 + 10.2 SD) at the first contact with CPS for an episode of major depression and we followed them up for 3 months. Main Measure Outcomes - At each visit we perform a clinical evaluation (HRS-D, CGI, DOTES) and we administered an interview to collect data in order to quantify social costs (direct and indirect) related to the observation period. Results - At the end of the 3 month period, all patients showed an improvement of the simptomatolgy as expressed by HRS-D (final score at least 50% below the initial one). Our accounting model estimated that the full cost of a psychiatric visit (on average lasting 47.8 minutes) is 107.537 Italian Liras. For the 10 patients under observation direct costs amounted to 9.402.000 It. Liras; psychiatric visits represented 70% of these costs. According to a conservative approach, indirect costs (value of labor time lost) amounted to 13.254.000 It. Liras if patients and relatives are considered and to 11.044.000 It. Liras if only patients time is evaluated. Conclusion - The paper presents a methodological proposal aimed to assess social costs of major depression. It also reports a first attempt to measure these costs in a prospective study performed in a public psychiatric centre. Our results have to be considered in the light of the limited sample of patients under observation and have to be regarded as strictly dependent on the specific context both in terms of the organizational settings and the characteristics of patients.