ABSTRACT This study discusses the design and development of a Visual Basic for Applications (VBA)-based purchasing and sales information system in Microsoft Excel at the Agist Elektronik Store. The main problems were manual transaction recording, which was prone to errors, difficult data retrieval, and slow reporting. The system was developed using the Waterfall method, starting with the analysis phase using the PIECES (Performance, Information, Economy, Control, Efficiency, Service) approach, design using context diagrams and level 0 DFDs, implementation of purchasing, sales, supplier, and customer forms, and black-box testing to ensure each function ran according to plan. The results showed that this system can accelerate transaction processing, improve data accuracy, and automatically generate purchasing, sales, and inventory reports. This system is expected to help improve efficiency, accuracy, and ease of data management at the Agist Elektronik Store. Keywords: VBA, Microsoft Excel, Waterfall ABSTRAK Penelitian ini membahas perancangan dan pembangunan sistem informasi pembelian dan penjualan berbasis Visual Basic for Applications (VBA) pada Microsoft Excel di Toko Agist Elektronik. Permasalahan utama adalah pencatatan transaksi yang masih manual sehingga rawan kesalahan, sulitnya pencarian data, serta lambatnya pembuatan laporan. Sistem dikembangkan menggunakan metode Waterfall, dimulai dari tahap analisis menggunakan pendekatan PIECES (Performance, Information, Economy, Control, Efficiency, Service), perancangan melalui diagram konteks dan DFD level 0, implementasi form pembelian, penjualan, supplier, customer, serta pengujian dengan metode black box untuk memastikan setiap fungsi berjalan sesuai rencana. Hasil penelitian menunjukkan bahwa sistem ini dapat mempercepat proses transaksi, meningkatkan akurasi data, dan menghasilkan laporan pembelian, penjualan, serta stok barang secara otomatis. Sistem ini diharapkan dapat membantu meningkatkan efisiensi, akurasi, dan kemudahan manajemen data di Toko Agist Elektronik. Kata kunci: VBA, Microsoft Excel, Waterfall