A survey of cucurbit fields was conducted in the September 2017 growing season in Oklahoma, USA. A total of 121 symptomatic leaf samples (103 from pumpkin and 18 from squash) showing mosaic, mottling, and chlorosis and 10 asymptomatic samples from pumpkin (Cucurbita pepo) were collected from grower's fields located in various counties. All samples were tested against the polyclonal antisera of 10 known cucurbit-infecting viruses including Papaya ringspot virus (PRSV), Watermelon mosaic virus (WMV), Zucchini mosaic virus (ZYMV), and Cucurbit aphid-borne yellows virus (CABYV, genus Polerovirus, family Luteoviridae) by dot-immunobinding assay (DIBA). Eleven out of 121 symptomatic samples (eight samples from Blaine County and three from Payne County) of pumpkin reacted positively against the antisera of CABYV by DIBA, and the remaining samples were positive to WMV, PRSV, and ZYMV. None of the asymptomatic samples were positive against the 10 viruses in the DIBA. To further confirm the CABYV infection in these pumpkin samples, four of the eleven CABYV-DIBA-positive pumpkin samples (one from Payne County and three from Blaine County) were randomly selected, and total RNA was extracted. PCR assays and nucleotide sequence analysis were carried out. The results indicate the first report of CABYV infecting cucurbits in Oklahoma.