We present absolute abundances and latitudinal variations of ozone and water in the atmosphere of Mars during its late northern spring (L s = 67.3 β’ ) shortly before aphelion. Long-slit maps of the a 1 g state of molecular oxygen (O 2 ) and HDO, an isotopic form of water, were acquired on UT January 21.6 1997 using a highresolution infrared spectrometer (CSHELL) at the NASA Infrared Telescope Facility. O 2 (a 1 g ) is produced by ozone photolysis, and the ensuing dayglow emission at 1.27 Β΅m is used as a tracer for ozone. Retrieved vertical column densities for ozone above βΌ20 km ranged between 1.5 and 2.8 Β΅m-atm at mid-to low latitudes (30 β’ S-60 β’ N) and decreased outside that region. A significant decrease in ozone density is seen near 30 β’ N (close to the subsolar latitude of 23.5 β’ N). The rotational temperatures retrieved from O 2 (a-X) emissions show a mean of 172 Β± 2.5 K, confirming that the sensed ozone lies in the middle atmosphere (βΌ24 km). The Ξ½ 1 fundamental band of HDO near 3.67 Β΅m was used as a proxy for H 2 O. The retrieved vertical column abundance of water varies from 3 precipitable microns (pr-Β΅m) at βΌ30 β’ S to 24 pr-Β΅m at βΌ60 β’ N. We compare these results with current photochemical models and with measurements obtained by other methods.