This article shows the results of an investigation about conceptions of nature of science –NoS- in group in-service teachers in natural science. From a qualitative perspective, the instrument that allowed to collect the information was the semi-structured in depth interview and the technique used was the content analysis. The interviewees were selected through an intentional sampling. In conclusion, in-service teachers have NdC conceptions built more from common sense, eclectic and with tendency towards positivism positions.