The aim of the current study was to identify different competencies developed through Continuous Professional Development (CPD) and to evaluate the effectiveness of mentoring in developing different competencies among primary teachers. It was a descriptive and quantitative study in nature. Primary school teachers (PSTs)from the district of Lahore were the population of the study. The sample was selected randomly from 10Percent of the total population (N = 786). For the data collection, a 5-point Likert-type questionnaire was developed by the searcher. To answer the research questions, data were analyzed using SPSS version 21 with mean SD, t-test, and ANOVA. The identified professional competencies through the CPD program were classroom management, micro-teaching, reinforcement, planning and strategies, learning environment,human growth and development, assessment, communication skills, asking questions, and lesson planning. Mentoring is recommended to be done at the elementary and secondary levels to develop competencies