The purpose of this study was to examine oral self-care behaviour and the prevalence of gingivitis and dental calculus in fathers of young families using a questionnaire. The participation rate at 18 months after the birth of the first child was 73.1%. The mean age of the respondents (n = 917) was 28.1 years (range 17-49; SD 4.6). Dental health and dental care were assessed by asking about the existence of gingivitis and dental calculus. Oral hygiene habits were analysed by asking about the use of toothpicks and dental floss and the regularity of toothbrushing. Gingivitis and dental calculus were found to be related to age and to educational and occupational status. The older respondents used dental floss and toothpicks more often and brushed their teeth more regularly than those in the younger age group. When the wife's knowledge was poor, the respondent's oral hygiene habits were also poor. If the wife's knowledge level was good, the young father's oral hygiene was good, too. Parents transfer their own oral health care habits to their children. Respondents whose parents had a high socio-economic status exhibited good oral hygiene habits. The Maternity Health Care Clinic and Well-Baby Clinic network can also influence oral health care habits. The relevant parts of general prophylactic guidance given at these clinics should be included in dental health programmes.