This study measures the impact of labor and corporate political action committee (PAC) contributions on the voting of members of the House of Representatives on labor issues during 1979–80. It also analyzes the allocation of labor PAC contributions among House candidates. PAC contributions were found to have a significant direct effect on roll-call voting, even controlling for the Representative's political party and characteristics of the constituency. Since PAC money also affects roll-call voting indirectly (by influencing which party wins elections), the overall impact of PAC money on Congressional voting is probably substantial. The author also finds that labor PACs have focused more on influencing the outcome of elections than on currying favor with powerful members of the House who are likely to be re-elected anyway.