The authors investigated whether there was a decline in infants sleeping prone and other modifiable risk factors for sudden infant death syndrome (SIDS) in Germany, where, as in some other countries, no nationwide intervention campaign against the prone sleeping position had been initiated. Data were obtained from parents by mailed questionnaires in two cross-sectional studies in 1991 (n = 3,330) and 1995 (n = 3,124). Prevalence of prone sleeping decreased from 37.6% to 8.7% (p < 0.05) in the German population and from 44.1% to 32.0% (p < 0.05) in the Turkish immigrant population. Parents who laid their infants prone in 1995 were less likely to follow advice from physicians, public media, and other parents (relative risks < 0.5, p < 0.05) and were more likely to have a low educational level, to be <20 years old, to be single parents, to have two or more children, to be raised in West Germany, or to be of Turkish ethnicity. Although the information on prone sleeping being a risk factor for SIDS became known among the population, these data suggest that subgroup-specific public intervention campaigns may be needed to reduce the prevalence of prone sleeping even further in those countries where no nationwide campaign has been initiated.