In this study, a fuzzy approach is presented for modelling of high strength concrete under uni-axial loading. Usually, experimental data cannot be defined by mathematical expressions easily, but the fuzzy approximation enables to describe the data more accurately. The fuzzy logic approach applied to test data of concrete cylinder test is available in the literature. In the present paper the stress-strain behaviour of high strength concrete subjected to axial load is obtained by using the fuzzy logic model. It is shown that the present model can predict the stress-strain behaviour of concrete accurately by taking into account the parameters of the problem. The results are compared with the analytical models given in various studies concerning cylinder tests. The new approach shows that there is no need to obtain different expressions for ascending and descending branches of the stress-strain behaviour. (C) 2012 Elsevier Ltd. All rights reserved.