This article reports a study on Czech basic colour terms, the aim of which was to establish their exact number. A basic colour term is understood as Brent Berlin and Paul Kay defined it in 1969. The data for the study was collected using the field method of Ian Davies and Greville Corbett (1994). Fifty-two native speakers of Czech, aged 15 to 70, performed two tasks: a colour-term list task and a colour naming task. The list task was complemented by the cognitive salience index designed by Sutrop (2001, 2002). An analysis of the results shows that there are exactly 11 basic colour terms in Czech bela 'white', cervena 'red', zluta 'yellow', modra 'blue', zelena 'green', cerna 'black', oranzova 'orange', fialova 'purple', hneda 'brown', ruzova 'pink', and seda 'grey'. Czech language does not possess an additional basic colour term ruda for red and there is no colour term meaning blue and yellow as been suggested in some studies. DOI: 10.3176/tr.2008.1.01 Keywords: basic colour term, cultural basicness, field work, Czech language, red, plavy