Most of the current Internet trading frameworks, in particular their negotiation and payment phases, are intended for customers frequently connected to the Internet during an entire transaction. This requirement cannot be easily met in the high communication cost and/or low bandwidth settings, typically found in mobile computing environments. Based on the software agent paradigm, a new secure agent-based framework for Internet trading in mobile computing environments is proposed in this paper. The framework is composed of two new protocols. One is the agent-based auction-like negotiation protocol, another is the agent-based payment protocol. Both of them are dedicated to solve the trade problems of Internet trading in mobile computing environments and ensured to be safe by cryptographic technologies. The combination of the two secure protocols constitutes an integrative solution for Internet trading in mobile computing environments.