The presence of Chlamydia (C.) psittaci, C. pneumoniae and C. trachomatis DNAs in MALT lymphomas of ocular adnexals from 13 Austrian patients were studied. Gastrointestinal MALT lymphomas and gastritis specimens served as controls. Of 13 MALT lymphomas of the ocular adnexals, seven were positive for C. psittaci DNA. In contrast, one of 17 gastrointestinal specimens tested positive. All specimens were negative for C. trachomatis and C. pneumoniae DNAs. In conclusion, C. psittaci infection was observed in the majority of MALT lymphomas of ocular adnexals in Austrian patients.