Purpose: The study aim was to provide basic data needed for formulating systematic visiting nursing strategies by comprehending the characteristics and self-care ability of the object families of public health centers in Korea. Method: The research examined 252 families and 339 family members of the vulnerable class that were registered in a visiting nursing program of an urban public health center. The data of 220 families were analyzed using descriptive analysis, t-test, and ANOVA, after excluding any incomplete data. Result: 1. The most frequent characteristics of families were solitary families (52.8%) and financially vulnerable families (87.3%). The most frequent way of family detection was request of the community office. 2. The most frequent type of family problems were vulnerable families (93.2%), followed by patient families (91.0%). 3. The mean score was 11.67 for family self-care ability. 4. The variables of the number of family members, disease type of the patient family members, and the type of vulnerable family showed a significant difference of family self-care ability. Conclusion: This study suggests that vulnerable families demand specific nursing interventions focused on their own problems and that visiting nurses need to obtain and use supportive resources.