Erythromycin (ERY) is one of the macrolides used abundantly in veterinary medicines to treat various infections including respiratory, skin and bones. Combination of sulfadiazine (SFD) and trimethoprim (TMP) has proven efficacy and is widely used in the treatment of many infectious diseases, due to the efficiency of SFD as a bactericidal and TMP as a bacteriostatic. On the other hand, those residues of antibiotics like ERY, SFD and TMP in animal tissues may pose health hazards to humans. A simple and cost effective TLC densitometeric method has been developed to analyze the above mentioned drugs in their dosage form and in spiked chicken muscle and liver samples. A mixture of chloroform: methanol: ammonia hydroxide solution (33%, v/v) (8.5:1.5:0.1, by volume) was the developing system. In order to obtain the highest possible sensitivity, the separated bands were exposed to iodine vapors in well closed container for 15 min and then detection was immediately done at 220 nm. Linearity was achieved in the ranges of 0.5–10, 0.1–2 µg/band for ERY and SFD, respectively in both spiked muscle and liver samples while for TMP, linearity was proved over the ranges of 0.1–1.8 µg/band for spiked muscle samples and 0.1–1.6 for spiked liver samples.