We studied the 5-HT1A receptor gene in 50 mood disorders and 50 normal volunteers. The 5-HT1A receptor gene was amplified by polymerase chain reaction and sequenced by the dideoxy method. The sequence of the 5-HT1A receptor encodes a protein of 422 amino acids, that is, one amino acid longer than the reported sequence (Kobilka et al. 1987). The DNA sequence at positions 454 to 459 is CGC GCC GCT, not CCG CGT, and the amino acids sequence at these positions is changing from proline arginine to arginine alanine alanine. These differences, however, were observed in both mood disorders and controls. One silent polymorphism, CTG to GTA at position 294, was found. These results suggest that the 5-HT1A receptor gene is intact in mood disorders.