A new dipstick immunoassay format for terbuthylazine determination, based on the use of polystyrol strips as antibody coating support, is described. Terbuthylazine calibration curve show linear measuring range between 1.2-10 mg/L and a practical detection limit of 1.2 mg/L. Real water samples were analysed and results correlate well with those from gas chromatography (GC/MS) and ELISA. No false negative results were evidenced.A dipstick immunoassay format for atrazine determination was also used for the analyses of the same samples. Some false positive results were obtained, probably due to cross-reactivity of the atrazine monoclonal antibody for terbuthylazine.At this developmental stage, these dipsticks can be very useful as qualitative/semiquantitative "field test" for identifying "positive" samples, reducing the number of samples to be reanalysed in laboratory according to analytical standard methods (GC). Further improvements are possible in order to optimise the whole system on the strictly analytical aspects.