Collision avoidance, one of the hottest subjects in the oil and gas industry, must be treated as high priority before executing any drilling programs. Wellbore collision avoidance procedures have a huge impact on the wellbore placement for targetson many desired reservoirs. A well planner/ drilling engineer must perform these procedures at the very beginning of the well planning stage, especially if the drilling involves platforms. Having a trusted historical database of the field is crucial, and this is where the integrity of the survey database and the survey programs provided by client must be reviewed very carefully. Any human error, software malfunction, or incorrect surveys can lead to major accidents at the rigsite, death of, worker injuries, environment pollution and financial losses. This paper discuss the basic clearance calculations that indicate how far away one wellbore is from another and the mitigation measures that should be followed to have a valid collision avoidance procedures.