We report the finding of Babesia EU1 and Babesia microti in Ixodes ricinus ticks in the Netherlands. During 5 years of surveillance between 2003 and 2007, 1488 ticks were collected in a dune forest area near the North Sea and were screened for Babesia infections. In 17 ticks, DNA of the protozoan parasite genus Babesia was detected using a Babesia-specific 18S rRNA polymerase chain reaction. Further, reverse line blot analysis and DNA sequence analysis showed that 13 of these ticks carried Babesia EU1, two ticks carried B. microti, and one tick carried B. divergens. This study shows that the human pathogenic species Babesia EU1 and B. microti can complete their life cycle in the Netherlands.