This study compared parental cognitions and relationship characteristics of mothers of children with atopic disease with those of mothers of children without atopic disease. These factors include child-rearing attitudes, parental locus of control, parental sense of competence, attachment security, and maternal sensitivity. Preplanned subanalyses were carried out according to specific disease, mothers’ perception of disease severity, and presence of concurrent atopic diseases. The descriptive comparative study of 233 Korean mothers included 102 mothers of children aged six years or younger with atopic dermatitis, asthma, and/or allergic rhinitis. Data were collected from 2007 to 2008 from local clinics and day care centers. Parental cognitions and relationship characteristics did not differ significantly between groups of mothers, except that mothers of children with atopic dermatitis showed less affection. However, subanalyses showed that mothers who perceived their child’s disease to be severe were less likely to encourage autonomy and had a lower sense of competence, more rejecting attitudes, and an external locus of control. Although we should be cautious in generalizing these results, special care plans are strongly recommended for mothers of children with severe atopic disease to provide support and education, help mothers develop an internal locus of control, and increase parental sense of competence.