The main objectives of this study were (i) to find out to what extent postnatal depression (PND) in mothers was recognized at Well Baby Clinics (WBCs) in Stockholm, (ii) to study the prevalence of PND using the Edinburgh Postnatal Depression Scale (EPDS), (iii) to test the positive predictive value of the EPDS against an interview-based Research Diagnostic Criteria (RDC) diagnosis of depression and (iv) to identify sociodemographic risk factors for PND. Case-records of 1128 infants were reviewed at WBCs to obtain a baseline rate of PND. Two per cent of the mothers were identified in the routine service of the WBCs as being depressed during the first 3 months postpartum. During a project year, 309 Swedish-speaking mothers completed a set of EPDS 3 months postpartum. In total, 14.5% of the women scored >12 on the EPDS and 67% of these women had a depression according to RDC. At least 8.4% of the mothers investigated had a clinical depression. A positive link was found between being single with more than one child and having PND. In conclusion, very few women with PND are identified in routine WBC care in Sweden. The use of the EPDS as a screening measure at the WBC is recommended. The scale is well accepted both by the mothers and by the nurses, and its use significantly increases the number of identified cases of PND.