The regions of existence are established for a class of two point nonlinear diffusion type boundary value problems (NDBVP)where a1 > 0, a2 ≥ 0, C ∈ R. These problems arise very frequently in many branches of engineering, applied mathematics, astronomy, biological system and modern science (see [1,3,4,8,14,15]). By using the concept of upper and lower solutions with monotone constructive technique, we derive some sufficient conditions for existence in the regions where ∂f ∂s ≥ 0 and ∂f ∂s ≤ 0. Theoretical methods are applied for a set of problems which arise in real life.