This descriptive research was conducted to determine the pre-service teachers' pedagogical content knowledge on problem-solving heuristics and mathematics content which served as bases for curricular enhancement in problem solving. The participants of the study were the seventy-nine (79) pre-service teachers taking up Bachelor of Elementary Education (BEED) who taught mathematics subjects during their practice teaching. The participants were purposely chosen from the five accredited Teacher Education Institutions (TEIs) in Iloilo City during the 2nd semester, school year 2012-2013. Of these 79 participants, twenty-seven (27) were purposely elected for classroom observations. The data-gathering instruments were the validated and trial administered researcher-made 10-item problem solving heuristics test, 75-item mathematics content test, 30-item Pedagogical Content Knowledge (PCK) test and observation guide. The results of the study showed that the knowledge of problem-solving heuristics of the pre-service teachers as an entire group and when further classified according to schools was low. It was confirmed during classroom observations that only few of the pre-service teachers used problem-solving heuristics in teaching problem-solving to the students. The result also revealed that the mathematics content and pedagogical content knowledge of the pre-service teachers as an entire group and when further classified according to schools were average. It as confirmed during classroom observations of the pre-service teachers that majority of them had applied their knowledge of mathematics content in teaching elementary mathematics to the students. Majority of them showed confidence in teaching the correct basic mathematical concepts ans principles. Moreover, majority of the pr-service teachers used their pedagogical content knowledge in teaching; they used different teaching strategies that were appropriate in their lessons. The participants were creative and resourceful in preparing their instructional materials. Based on the results and findings, a curricular enhancement in problem solving was developed to help improve the problem- solving heuristics, mathematics content, and pedagogical content knowledge of the pre-service teachers. The curricular enhancement output is an enriched course syllabus in problem solving. The topics included were Problem Solving Framework, Heuristics, Routine and non-routine problems, and problem formulation and posing. The enhancement outputs are reflected in Worksheet 1-0. Each worksheet contains an illustrative example, enrichment activity, assessment and the related PCK situational items as well as basic mathematical skills.