To provide information about persistent infant crying, crying durations and patterns were measured at four age points (1-3, 4-6, 7-9 and 10-12 months) in normal community (N = 400) and clinical (N = 68) samples. The findings provide a range of prevalence figures and descriptive statistics which may be useful for parents and professionals faced with infant crying. A large developmental shift in crying amount, and two age-related changes of crying pattern, were found. Clinical infants showed the same crying profiles as the general community infants, but were found to cry substantially more. Although mothers of first-borns were more likely to seek clinical referral, there were no birth-order differences in crying amount or pattern. The findings' implications for studies of infant temperament and development are indicated.