Cilj: Otkrivanje mikrodelecije AZF (engl. azoospermia factor) područja kromosoma Y u muškaraca s teškim poremećajem spermatogeneze važno je zato što se metodama medicinski potpomognute oplodnje mikrodelecije prenesu na 100% muškog potomstva. Ispitanici i metode: Istražili smo prisutnost mikrodelecija Y kromosoma u 129 muškaraca s područja Istre i Primorja. Kliničke dijagnoze ispitanika bile su: azoospermija (N=33), teški oblik oligozoospermije (broj spermija manji od 5 milijuna/ml; N=25), oligozoospermija (N=47) i astenospermija (N=24). Neplodnost nepoznata uzroka imala su 84 ispitanika, dok su u ostalih utvrđeni još i hipogonadizam, kriptorhizam ili varikokela. Molekularno-genetička analiza napravljena pomoću četiri multipleks i jedne simpleks lančane reakcije polimeraze obuhvatila je 12 STS lokusa-biljega. Analizirani su STS-biljezi: sY84, sY86, sY127, sY134, sY254, sY255, kontrolni biljeg sY14 (SRY) i pseudoautosomski lokus ZFX/ZFY prema preporuci Europske androloške akademije. U ispitanika u kojih su pronađene mikrodelecije analizirani su dodatni STS-biljezi: sY87, sY88, sY114, sY135, sY152 i sY157 radi utvrđivanja njihova opsega. Rezultati: Mikrodelecije su pronađene u dva ispitanika (2/129 ili 1,55%). Obojica su imala kliničku dijagnozu idiopatske azoospermije. Učestalost mikrodelecija u grupi s azoospermijom iznosi 2/33 ili 6,06%, a u grupi s idiopatskom azoospermijom 2/18 ili 11,1%. Mikrodelecije nisu pronađene u ispitanika s ostalim dijagnozama neplodnosti, kao niti u kontrolnoj skupini muškaraca (N=100). U jednog ispitanika mikrodelecija je zahvatila AZFc potpodručje, dok se u drugoga proteže kroz AZFb i AZFc potpodručja. Zaključak: Učestalost mikrodelecija Y kromosoma niža je u našem uzorku ispitanika nego što je objavljeno za većinu europske populacije. U našoj populaciji pronalazak mikrodelecija AZF područja kromosoma Y povezan je s idiopatskom azoospermijom., Aim: The detection of microdeletions of AZF (azoospermia factor) region of Y-chromosome in men with severely impaired spermatogenesis is important since Y-chromosome microdeletions are transmitted to 100% of male offspring when using assisted reproduction methods. Subjects and methods: We investigated the presence of chromosome-Y microdeletions in 129 men from North-Adriatic region of Croatia. Their clinical diagnoses were: azoospermia (N=33), severe oligozoospermia (sperm count less than 5 million/ml; N=25), oligozoospermia (N=47), and asthenospermia (N=24). Eighty four of them had idiopathic infertility, while the rest of them were also diagnosed with hypogonadism, cryptorchidism or varicocele. Molecular-genetic analysis was performed using four multiplex and one simplex polymerase chain reaction (PCR). Twelve STS-markers were investigated. STS-markers: sY84, sY86, sY127, sY134, sY254, sY255, control marker sY14 (SRY), and control pseudoautosomal locus ZFX/ZFY were analyzed according to recommendation of European Academy of Andrology. In cases of detected microdeletion six additional markers were analyzed: sY87, sY88, sY114, sY135, sY152, and sY157. Results: Microdeletions were found in two men (2/129 or 1,55%). Both men were diagnosed with idiopathic azoospermia; therefore the frequency of microdeletions in the azoospermia group was 2/33 or 6,06%, while in the idiopathic azoospermia group was 2/18 or 11,1%. Chromosome Y microdeletions were not found in non-idiopathic infertility group nor control men (N=100). Conclusions: The frequency of microdeletions was lower in our sample than reported for many European populations. Idiopathic azoospermia carries the risk for diagnosis of Y- chromosome microdeletions in our population.