One of the active trace gases that influences the ozone distribution is nitrogen dioxide (NO2). Since the role of NO2 in the photochemistry of ozone is strongly dependent on altitude, it is important to know not only the NO2 total amount, but also its vertical distribution. In this paper, we use the approach proposed by Preston et al. [1] to retrieve NO2 altitude profiles from slant column measurements. The observations were made with a portable UV-visible spectrometer operated on the ground during the Middle Atmospheric Nitrogen TRend Assessment (MANTRA) balloon campaign carried out at Vanscoy, Saskatchewan, Canada (52degrees N, 107 W), from 18 to 25 August 1998. The NO2 profile retrieved from the ground-based observations is compared with the co-located and simultaneous NO2 profile measured by a balloon-borne UV-visible spectrometer during sunrise on August 24. Finally, the retrieved profiles are compared with the output of the MEZON 3D stratospheric chemical transport model and the results are discussed.