The aim of this article is to analyse the impact of European and Slovak legislation on small and medium-sized enterprises during the period of observation. The basis for determination of small and medium-sized enterprises/SMEs/is the definition of the European Commission. The fundamental legal regulation determining constraints of business is our Commercial Code. The definition of SMEs has been implied in our legislation only since 1995 as amended by Act no. 100/95 Coll. of laws regarding to state aid for SMEs. By comparison of the economic development and the legislation development in this area, in Article we want to point out whether the legislation has had a positive or negative effect on small and medium-sized enterprises within observed period.