In this study, a new approach is developed for predicting stress-strain curve of steel fiber-reinforced concrete (SFRC) under compression, by use of fuzzy logic system (FLS). In the coverage of study, firstly, experimental studies were carried out. Cylindrical specimens were prepared in size of 0150 x 300 mm with and without steel fiber. Two different steel fiber types (both are hooked end) were used as ratios 0 (control), 15, 30, 45 and 60 kg/m(3). The stress-strain curves were defined for 28 ages of the cylindrical specimens. Secondly, the stress-strain curves for SFRC were modeled by use of fuzzy logic approach, and the results that were obtained from experiments and modeling were compared. As a result close relationship between both results was seen. (C) 2006 Elsevier Ltd. All rights reserved.