In this paper, adaptive fuzzy multiuser detection for OFDM communication systems is proposed. The enhanced adaptive fuzzy detection capabilities enable to increase performance and capacity of OFDM systems. In the proposed paper, adaptive fuzzy multi-user detectors are constructed using a set of fuzzy IF-THEN rules, which are changed adaptively using Least Mean Squares (LMS) and Recursive Least Squares (RLS) algorithms to minimize the bit error rate (BER). Parameters of the fuzzy detectors are adjusted during a short training period, enabling adaptation to changing conditions. Detection results are compared to the conventional detector, and it is shown that fuzzy multiuser detection outperforms the conventional detector. The main advantage of fuzzy detection is that linguistic (fuzzy IF-THEN rules) and numerical information (input-output pairs) can easily be combined into the detectors.