Objective. To study the alcohol effect on chronological rhythms of suicidal activity in patients supervised by addiction treatment specialists and psychiatrists. Material and methods. We have analyzed 1094 cases of suicides committed by men who lived in Cheboksary and Novocheboksarsk. The suicide committers were divided into two groups by presence or absence of blood and/or urine alcohol; each group was subdivided into three subgroups: a) mentally healthy suicide committers (MHSC), b) those who were under the supervision of the psychiatrist (PS), c) those who were supervised by addiction treatment specialists (ATS). Chronobiological rhythms were assessed using z-scores, frequency biological rhythms were evaluated with Kolmogorov—Smirnov’s test with the Lilliefors correction and rank correlation. The trends of each chronobiological number were computed, the differences of obliquing angle of the trend were evaluated using 2×2 contingency tables (c2 with Mac-Namara’s amendment). Results. All suicide committers of the 1st group showed daily rising suicide trend, which had highs in the active wakefulness period. In the 2nd group, the trend did not change in MHSC and ATS, but in PS it significantly changed to descending with two peaks at 6—8:59 and 18—20:59. Upward weekly trend in PS in both groups was almost the same (in the 1st group the obliquing angle of the trend was 19° and in the 2nd group — 21°), the maximum was observed on Saturday and Sunday. In MHSC of the 1st group, the trend was moving downward, and in the 2nd group it was low. Both MHSC and ATS had the maximum on Monday. Annual trend in the 1st group in all samples was low. In the 2nd group, the trend remained low at MHSC and ATS and changed up in PS (16°) with the maximum in November—December. Conclusions. Chronobiological characteristics of deaths confirmed by peaks exceeding the average proportion of suicides from 1.5 to 2.5 times were noted in all groups of suicide committers. Alcohol intake significantly changed the suicidal chronobiological rhythm in PS.