Viruses caused severe yield losses of field cucumber in Hungary last years. Field surveys have been carried out on field cucumber to evaluate virus infection in the region of Gyor-Moson-Sopron county. Virus infection was determined on the basis of symptoms, biotest and with DAS-ELISA serological method for the presence of 15 viruses. The virus vector aphid flight was monitored by Moericke yellow water pan. On the basis of field surveys 100% virus infection has been observed in cucumber fields. Virus symptoms were various, depending on varieties, environmental factors, viruses and strains. Out of the viruses investigated only three [Cucumber mosaic cucumovirus (CMV) (DTL serotype); Zucchini yellow mosaic potyvirus (ZYMV) and Watermelon mosaic 2 potyvirus (WMV-2)] have been occurred on cucumber samples. Biological tests confirmed the results of DAS-ELISA. There was much difference, regarding the frequency of viruses. ZYMV was dominant in 1998, while CMV was dominant in 1999. The proportion of the complex infection was very high. Till now, besides CMV other viruses cannot be detected from weeds in cucumber ecosystems. The peak of aphid flight was in the middle of June and later a secondary peak was observed at the beginning of July, which coincided with the appearance of the first virus symptoms. Regarding, that cucumber production occurs in fields at the same place year by year, soil borne virus vectors may play important role in virus infection. To reduce virus infection we can suggest using of light summer oils, which prevents virus transmission by aphids. It is concluded that team work of virologists, pathologists, growers, technologists and the breeders is necessary to solve virus problems of field cucumber in Hungary.