It is a non-technical description of various issues that arise in sample selection for marketing research studies. Users' point of view has influenced the content and the style of writing of this note. It draws upon the experience of actual marketing research studies which are included as illustrations. It deals with various steps in sample design, like definition of universe, preparation of sampling frame, choice of basic sampling approach, probability, non-probability and Bayesian sampling methods, problems of sampling in experimental marketing research, and problems in actual implementation of a sampling plan.