OBJECTIVES: After unification in 1990 the two parts of Germany underwent a complex process that has led to convergence of infant mortality. The pattern of change did, however, differ in east and west. This study investigates whether these differences conceal a complex pattern of heterogeneity at the regional level. METHODS: Examination of routine data on infant, neonatal and postneonatal mortality. Time trends in the 16 federal states of Germany (Länder) from 1991 to 1997 were studied using a log-linear model. RESULTS: In 1991, infant mortality was higher in almost all eastern Länder than in the west. By 1997, this east-west gap had disappeared. Over this period, infant mortality fell in all Länder but one. The decline was steepest in the east, ranging from 31% to 52%. Improvements were largely due to steep declines in both neonatal and postneonatal mortality. CONCLUSIONS: This study shows that, at the time of unification, there was an almost complete demarcation between east and west, a pattern that disappeared by 1997. There is, however, still a substantial regional variation in infant mortality that is largely determined by postneonatal mortality.