Empirical data gathered from surveys of MPs and interest groups in Slovenia reveal that the National Assembly of the Republic of Slovenia is a relatively powerful and accessible political institution. Parliamentary working bodies are perceived by MPs and interest groups as the focal point of their contacts. While MPs find interest groups to be both valuable sources of input into the legislative process and relatively influential policy actors, interest groups are relatively happy with how accessible MPs are, though they are less happy with their own impact on parliamentary decision-making. Despite the direct exchange between MPs and interest groups, political parties still play an important gate-keeping role. The identified factors of the impact of interest groups on the legislative process include the formally defined roles and competencies of parliamentary working bodies, policy sector variations, European interest-group networking, and the leadership styles of those who chair the working bodies.