EN
Thermal expansion studies on (CH_{3}NH_{3})_{5}Bi_{2}Cl_{11} and (CH_{3}NH_{3})_{5}Bi_{2}Br_{11} in the temperature range 80-350 K are reported. The dilatometric measurements revealed a considerable similarity with respect to the anisotropy of dilatations of both isomorphous crystals. A diffused thermal anomaly was found around 170 K in (CH_{3}NH_{3})_{5}Bi_{2}Cl_{11} crystal.