The effect of 32 weeks' alcohol treatment on the number and affinity of dopamine and muscarinic receptor sites in rat striatum were measured using 3H-spiperone and 3H-quinuclidinylbenzilate (3H-QNB) as radioligands. The number of dopamine receptor sites was 38 per cent and the number of muscarinic receptor sites 36 per cent lower in the alcohol group than in control rats. The differences in receptor affinities were less marked. In conclusion, a long-term alcohol intake with rather moderate doses seems to induce a pronounced down-regulation in dopamine and muscarinic receptor systems in rat striatum.