Sampling and sample size play significant roles in the reliability of a research study. Unsuitable, inadequate or disproportionate sample sizes may result to unreliable and inaccurate research outcomes. This study therefore emphasized on the importance of sampling and determination of sample size in survey research.  The study also reviewed the criteria for a good sample size as well as factors that determine sample size decision. Methods of determining appropriate sample size were explained while Taro Yamane’s, Krejcie and Morgan’s and Cochran’s formulae of calculating sample size for survey research were objectively discussed. The study thus recommended as a matter of importance that determination of an appropriate sample size should be given high priority by researchers carrying out a survey research and that for finite population, any of the three formulae examined i.e. Taro Yamane’s, Krejcie and Morgan’s and Cochran’s formulae can be used to calculate sample size since it has been established that there is no material difference among sample sizes obtained through these formulae.