Bean golden yellow mosaic virus (BGYMV) is a geminivirus transmitted by whiteflies (Genus: Bemisia). This virus causes significant fosses in common bean (Phaseolus vulgaris L.). Serological techniques such as enzymelinked immunosorbent assay (ELISA) have been widely used for detection of viruses. We evaluated existing monoclonal antibodies (3F7, 2G5 and 5C5) for the detection of BGYMV isolates in bean fines in Puerto Rico. Monoclonal antibody 3F7 was the most effective in detecting the virus in tissues of line DOR 364 and susceptible cuftivars Top Crop and Quest. However, it was not effective in the detection of BGYMV in lines of DOR 303, which showed typical symptoms. Sampfes from Macroptilium lathyroides, a weed that might be a possible reservoir of the virus, were also tested for viraf infection. ELISA tests were inconclusive for detection of geminiviruses in M. lathyroides. Polymerase Chain Reaction (PCR) was also used to complement BGYMV diagnosis in M. lathyroides and in bean lines that showed symptoms but were negative for the ELISA test. Two sets of primers, specific for Begomovirus such as BGYMV, were used in PCR experiments. Using PCR, we were able to detect the virus in the line DOR 303 and in M. lathyroides tissues.