The aim of the present work was to identify cryptic species in the Anopheles maculipennis and Culex pipiens complexes and to study the genetic structure of the dominant mosquito species Ochlerotatus caspius (Diptera: Culicidae) in the Province of Alessandria close to the vast area untreated rice fields in Piedmont, NW Italy. With the help of PCR-RFLP analysis, four members of the Anopheles maculipennis complex were identified: A. messeae, A. maculipennis, A. sacharovi and A. atroparvus. Only C. pipiens f. molestus was identified in 11 habitats studied in Piedmont. Partial sequences of the cytochrome c oxidase subunit 1 (COI) mitochondrial gene and the second internal transcribed spacer (ITS2) of nuclear ribosomal RNA genes for Italian O. caspius are reported here for the first time. The results indicate that this species diverged from Iranian representatives of this species about one million years ago. The great diversity of mosquito species in Piedmont considerably increases the risk of vector-borne diseases. and Asghar TALBALAGHI, Elena SHAIKEVICH.