In this paper, we consider the detection of turbo coded symbols in orthogonal frequency division multiplexed (OFDM) systems and propose a turbo detector composed of a turbo decoder and a channel estimator. These modules perform jointly and exchange a soft information through an iterative process. The decoder consists of the maximum a posteriori MAP-BCJR algorithm and the channel estimator is based on the minimum mean square error (MMSE) criterion. The proposed approach allows for the use of all available information, increases the quality of channel estimation and improves the system performance. Simulation results for rate 1/3 turbo code show the efficiency of the proposed detector.