The study aimed at assessing possible relationship between behaviour features during sleep and temperament covered period from 2001 to 2002 and comprised 115 randomly selected, apparently healthy infants from the community setting, aged two months who were singletons born at term with normal weight (>2500 g). Early Infancy Temperament Questionnaire was used to describe different aspects of infant temperament: activity, rhythmicity, approach, adaptability, intensity, mood, persistence, distractibility and threshold. Infant behavioural features during sleep were estimated using modified Children's Sleep Habits Questionnaire. The infants with more negative mood more often required rocking or rhythmic movements to fall asleep, resisted sleeping alone, slept too little, were restless and moved a lot during sleep, woke up during night screaming, sweating and being inconsolable; less often could return to sleep after waking without parental interference. Infants with higher intensity less often fell asleep alone. More active infants less often slept about the same amount each day. Less distractible babies were less often ready to go to bed at bedtime, more frequently resisted going to bed at bedtime, were reluctant to sleep alone, slept too little and less often slept about the same amount each day. More rhythmic infants were more often ready to go to bed at bedtime and less often resisted going to bed at bedtime; less often they slept too little, were restless and moved a lot during sleep, woke up very early in the morning.