The serological assay for the detection of bacterial wilt caused by Ralstonia solanacearum (RS) was able to provide information regarding the presence of the pathogen in plant materials. The research is was aimed to develop polyclonal antibody (PAb) for RS detection. Bacterial whole cells of RS isolates mixed with glutaraldehyde were used to immunize New Zealand female white rabbit. The titre of antibody in culture supernatant was 1: 1024. The PAb developed from a ground nut RS isolates reacted with infected plant samples from various locations. It was able to detect RS antigen of crude extract and pure cultures from tomato and potato plant samples 4-5 using dot blot ELISA; however, the minimum detectable concentration of RS antigen was 10cells/ml. The PAb obtained in this study is sensitive enough to detect RS isolates in routine serological assay.