Rhodamin B is a green powder synthetic dye used as a textile dye and is often used to color a food product, especially tomato sauce. Tomato sauce sampled in Samarinda Morning Market for 5 samples. This research used color reaction test and KLT method. The result of the research using color reaction test showed that the sample did not contain rhodamine synthetic dye B. The result of identification with thin layer chromatography obtained Rf value of A sample 0,46, sample B 0,46, sample C 0,4, sample D 0,5 and sample E 0.78, the value of Rf standard rhodamin B 0.8. From the value of Rf, the sample E contains rhodamine B because the color of the sample spots and rhodamin B are the same pink and the difference of Rf value is in the range ± 0.02 of the standard Rf.