We discuss the existence of positive solutions for singular secondorder boundary value problems x′′ = μf (t, x, x′), ax(0) − bx′(0) = k ≥ 0, x′(∞) = 0, where f may be singular at x = 0 and x′ = 0 and can change sign. Via fixed point theory, we establish the existence of positive solutions under some conditions on f . Our results deal with the situation where the solutions approach the singulari...