Summary. Ocular manifestations in patients with Lyme borreliosis in northwest Croatia that occurred during the period between 1992 and 2001 were retrospectively analysed. The diagnosis of Lyme borreliosis was based on medical history, clinical mani- festations, epidemiological data about tick contact, determinations of antibodies to Borrelia burgdorferi by serological assays, immunoblot analysis, therapeutic results and exclusion of other infectious agents of ocular disease. Of the eleven patients reported here with clinical manifestations of ocular Lyme borreliosis, 6 had chorioretinitis, 1 papillitis, 2 iridocyclitis, 1 occlu- sion of the arteriae centralis retinae, 1 neuritis retrobulbaris and 1 neuroretinitis. Diagnostic confirmation of LB was in most patients done by serological tests and/or by immunoblot method in serum. In the last few years we have also done culture and molecular diagnostic methods polymerase chain reaction (PCR)) in serum and cerebrospinal fluid. The patienst were treated with 2 g of ceftriaxon IV per day for 14–21 days and/or with doxucyclin orally in a daily dose of 2×100 mg for 2–4 weeks. The therapeutic effect was followed up by regression of clinical symptoms (better visual acuity of the infected eye) and in changing of the specific antibody titer in serological tests. The authors emphasise the more detailed diagnostic proceedings of ocular Lyme borreliosis in patients with suspected Lyme borreliosis, an algorithm which contains data about residence in endemic area for LB, positive contact with ticks and/or the history of erythema migrans or any other Lyme borreliosis-like symptoms. For diagnostic confirmation it is necessary to use enzymeimmunoassay and immunoblot methods in serum, cerebrospinal fluid and aqueous humor, and isolation by culture or PCR can be used in the same diagnostic samples. Ocular Lyme borreliosis is an underdiagnosed disorder, because it is often unrecognised by ophtalmologists and due to weak seropositivity and seronegativity in the late ocular Lyme borreliosis. This is especially important in a highly endemic area for Lyme borreliosis like northwest Croatia, a border area of the central European andemic area ofr Lyme borreliosis.