We investigated the relationship between diabetes family conflict and parental conflict on problem recognition in illness self-management (PRISM) among individuals with type 1 diabetes mellitus (T1DM). We employed a descriptive research design. Participants were 243 individuals with T1DM who completed online questionnaires. Data were analyzed with descriptive statistics, correlations, and multiple regression analyses. Results revealed that barriers were felt in all areas (understanding and organizing care, regimen pain and bother, healthcare team interaction, family interaction, and peer interaction), especially peer interaction. The significant influencing factors in the regression model for the total PRISM score of individuals with T1DM were conflict behavior toward mothers (t = 4.44, p < 0.001), diabetes family conflict (t = 5.77, p < 0.001), conflict behavior toward fathers (t = 2.58, p = 0.011), women (t = 2.67, p = 0.008), non-religious (t = −2.33, p = 0.020), and diabetic complications (t = 2.17, p = 0.031). The explanatory power of the constructed regression model for PRISM was 42.0% (F = 30.12, p < 0.001). To promote self-management among individuals with T1DM, the development of interventions that promote improved peer interactions, a family-centered approach, and a program that can minimize conflicts between families and parents are required.