a b s t r a c tIn the present paper we extend the fourth order method developed by Chawla et al. [M.M. Chawla, R. Subramanian, H.L. Sathi, A fourth order method for a singular twopoint boundary value problem, BIT 28 (1988) 88-97] to a class of singular boundary value problemsa non-negative function. The order of accuracy of the method is established under quite general conditions on f (x, y) and is also verified by one example. The oxygen diffusion problem in a spherical cell and a nonlinear heat conduction model of a human head are presented as illustrative examples. For these examples, the results are in good agreement with existing ones.