Soil is a naturally occurring material, so considering spatial variability residing in soil properties seems logical. Assessment of Probability of Failure (PF) adds more aspect to the determination of the safety of a system. In this study, probabilistic analysis along with deterministic analysis is carried out for different slope angles and variation levels of shear strength properties. The deterministic factor of safety, probabilistic factor of safety and probability of failure are calculated for different slope geometries with and without consideration of cross-correlation between cohesion and friction angle under static conditions. The effect of different variation levels on slope under dynamic conditions is also studied. Three different LEMs have been utilized for analysis, and random variables are considered to follow normal distribution. The results prove that FOS and PF have an inverse relationship which is non-linear, but their non-linearity is greatly affected by COV levels. Results prove that the critical slip surface with minimum FOS obtained through deterministic analysis may not be the critical slip surface after all. Probability of failure (PF) more than 10% is not acceptable in any case. Probabilistic analysis along with deterministic analysis should be carried out to fully consider the geotechnical risk and hazard.