Saccharomyces cerevisiae (S. cerevisiae) (commonly known as baker’s yeast) is a model organism that has a similar upstream base excision repair (BER) pathway for the repair of methylated bases as that in mammalian cells, and it is very easy to maintain in the laboratory environment. Here, we described a method to prepare cell extracts from yeast to investigate their enzymatic activities. This protocol is a quick and efficient way to make yeast cell extracts without using commercial kits.