Tujuan penelitian ini adalah menghasilkan perangkat pembelajaran bangun ruang dengan pendekatan Creative Problem Solving  yang berkualitas baik berdasarkan kriteria valid, praktis, dan efektif. Jenis penelitian ini adalah penelitian dan pengembangan dengan model pengembangan Four-D yang diadaptasi dari Thiagarajan, Semmel, dan Semmel yang memuat tahap define, design, develop, dan disseminate. Penelitian ini menghasilkan perangkat pembelajaran yang terdiri dari Rencana Pelaksanaan Pembelajaran (RPP), Lembar Kegiatan Siswa (LKS), tes prestasi belajar, dan tes kemampuan penalaran matematis. Hasil validasi menunjukkan bahwa perangkat yang dikembangkan memiliki kategori sangat valid untuk masing-masing RPP, LKS, dan tes. Hasil uji coba menunjukkan bahwa RPP dan LKS yang dikembangkan memiliki kategori praktis dan efektif. Kepraktisan mencapai kategori sangat praktis berdasarkan penilaian guru dan mencapai kategori praktis berdasarkan hasil observasi keterlaksanaan pembelajaran dan penilaian siswa. Keefektifan mencapai kategori efektif berdasarkan ketuntasan belajar siswa. Secara klasikal ketuntasan tes prestasi belajar mencapai 76,67% dan tes kemampuan penalaran matematis mencapai 90%. Kata kunci: pengembangan, perangkat pembelajaran, Creative Problem Solving   Developing of Solid Instructional Package with Creative Problem Solving Approach   Abstract The aim of this research was to produce the solid instructional package with Creative Problem Solving  approach which have good quality based on the validity, practicality, and effectiveness criteria. This study was a research and development using the developmental model adapted from Thiagarajan, Semmel, and Semmel included define, design, develop, and disseminate stages. This study produces instructional package consists of lesson plans, student worksheets, achievement tests, and mathematical reasoning tests. The results of the validation showed that the developed package is very valid based on lesson plans, student worksheets, and tests. The results of the tryout indicated that lesson plans and student worksheets are practical and effective. The practicality was in  very practical category based on teacher’s assessment and practical category based on the implementation of learning and student’s assessment. The effectiveness was in the effective category based on student’s learning mastery. In the classical mastery learning it reached 76.67% for achievement and 90% for mathematical reasoning.   Keywords: development, instructional package, Creative Problem Solving