The purpose of this exploratory study was to identify the pattern of public health nursing service provided to substance-using mothers and their infants. To determine the effectiveness of public health nursing in a later randomized clinical trial (subsequent study), the first essential step was to identify clearly the nursing services that would constitute the intervention. For consistency, a clinical-practice checklist was developed by the public health nurses (PHNs) with the assistance of the investigators. Over a 6-month period, six PHNs made home, telephone, and office or clinic visits to mothers and their infants who were referred for follow-up due to a positive toxicology screen test at the time of delivery. For this client group (N = 28), the PHNs made one or two home visits to 17 mothers (61%), one or two telephone visits to 12 mothers (43%), and one or two office or clinic visits to 5 mothers (2%). Nearly one third of the time (29%), home-visit attempts were unsuccessful, and the client attrition rate was 50%. Polydrug use was common in this group, with 71% using two or more substances at the time of delivery. Referrals to substance-abuse treatment programs were usually not accepted by the clients, and many referrals were made for medical care and infants supplies. The most frequently mentioned area for advocacy was housing. Overall, public health nursing services were provided in a very limited time span of client availability.