We compared measurements taken by two satellite-borne instruments, ILAS-II and MIPAS-Envisat, between May and October 2003. Using the coincidence criteria of ±300 km in space and ±12 h in time for H<sub>2</sub>O, N<sub>2</sub>O, and CH<sub>4</sub> and the coincidence criteria of ±300 km in space and ±6 h in time for ClONO<sub>2</sub>, O<sub>3</sub>, and HNO<sub>3</sub>, a different number of coincidences have been found for the gases. The data were separated into sunrise and sunset measurements, which correspond to Northern and Southern Hemisphere data, respectively. For the sunrise data of ILAS-II, a clear improvement from Version 1.4 to Version 2.1 was observed for H<sub>2</sub>O, CH<sub>4</sub>, ClONO<sub>2</sub>, and O<sub>3</sub>. For ILAS-II N<sub>2</sub>O and HNO<sub>3</sub> data there were no large differences between the two data sets. In particular, the ILAS-II Version 1.4 data were unrealistically small for H<sub>2</sub>O, CH<sub>4</sub>, and O<sub>3</sub> and unrealistically large for ClONO<sub>2</sub> above 20 km to 30 km. The differences between the two algorithm versions for the sunset data were not as large as for the sunrise data for all gases, and for H<sub>2</sub>O and CH<sub>4</sub>. ILAS-II Version 1.4 data fitted even better to the MIPAS-Envisat measurements than Version 2.0.