The study aimed to examine possible association between degree of maternally reported eight-month-old infants' separation anxiety and their bedtime resistance. It comprised 114 apparently healthy babies (50 boys and 64 girls), who were born in St Petersburg in 2007. The infants were born at term (gestational age greater than or equal to 37 weeks), had birth weight appropriate for gestational age, and without any signs of inborn malformations, intrauterine infections, and inherited or progressive diseases. Information about infant, maternal, and demographic major characteristics was collected from available medical documents, as well as from maternal interviews. Eight babies (7%) were characterised as almost never having the signs of separation anxiety; 11 (10%) had them rarely; 33 (28%) had variable, usually did not; 26 (23%) had variable, usually did; 24 (21%) had frequently; and 12 (11%) had almost always. Statistically significant association was found between the infant separation anxiety frequency category and the bedtime resistance score (Kruskal-Wallis test: P less than 0.0001). Post-test analysis found statistically significant linear trend, in that the increasing frequency of the infant separation anxiety positively correlated with the increasing values of bedtime resistance score (Spearman rho = 0.99; "P"-value (two-tailed = 0.0028). Statistically significant association between the degree of infant separation anxiety and the bedtime resistance score remained after adjustment for major potential confounders. Separation anxiety may serve as a predisposing factor to bedtime resistance in eight-month-old infants. (Contains 2 tables and 1 figure.)