The purpose of this thesis was to identify how a child should be prepared to venous blood sampling and to survey, how the parents had prepared their children to the sampling situation. The aim was to provide information about how a child should be prepared to venous blood sampling. The material for the thesis was collected using a quantitative research method. A survey was made for the parents whose children (between the ages of 2 and 6) came to the venous blood sampling and for the biomedical laboratory scientists who work in the laboratory. In addition to the research child psychiatrist Hanna Manninen was interviewed about the subject. On the basis of the results and the interview it can be stated that having a discussion with the child about the blood sampling is the most important and most commonly used way of preparation to the venous blood sampling. A widely used and effective preparation method is also EMLA. Other good preparation methods are explaining the importance of sampling, guiding child's thoughts elsewhere and rewarding the child in small-scale. This thesis gives a good view of how children should be prepared to venous blood sampling. The study produced additional information about the preparation of children to venous blood sampling, even though the generalizability of the results is poor due to the limited number of parents participating. The thesis will be useful when searching information on the preparation of children to venous blood sampling.