Neonaticide is a sad and infrequent crime with possibly a high level of underreporting. The aim of this study was to examine the circumstances of neonaticide, and whether there are subtypes of offenders, or suggestions for prevention. The study was retrospective and register-based using comprehensive nation-wide material of all cases of suspected neonaticide during 1980-2000 in Finland. Out of the 50 suspected cases, 32 women were included in the final analyses as neonaticide offenders. Most women (91%) had concealed their pregnancy, which was not the first for 66%. Most (66%) were not quite sure why they had offended, and the most frequent (63%) method of operation was neglect. Four women were diagnosed psychotic and formed a specific group. We concluded that there might be specific subgroups of offenders - even though our small population limited conclusions. Furthermore, prevention might be heightened. We call for international joint projects for enlarged material to enable grouping, as well as education and discussion among the public and the professionals to prevent neonaticide, unify its jurisprudence and improve the treatment of the offenders.