The goal of this paper is to isolate the preparatory effects of problem-generation from solution generation in problem-posing contexts, and their underlying mechanisms on learning from instruction. Using a randomized-controlled design, students were assigned to one of two conditions: (a) problem-posing with solution generation, where they generated problems and solutions to a novel situation, or (b) problem-posing without solution generation, where they generated only problems. All students then received instruction on a novel math concept. Findings revealed that problem-posing with solution generation prior to instruction resulted in significantly better conceptual knowledge, without any significant difference in procedural knowledge and transfer. Although solution generation prior to instruction plays a critical role in the development of conceptual understanding, which is necessary for transfer, generating problems plays an equally critical role in transfer. Implications for learning and instruction are discussed.