Introduction: The exposure of gestating mothers to physicochemical factors may be associated with increased risk of multiple sclerosis (MS) in offspring. Method: The aim of this study was to determine whether solar radiations (SOR), ultraviolet B (UVB) rays, total ozone concentration in the atmosphere (TOCA) and air temperature (AT) during pregnancy are associated with MS developing in offspring. Demographic and diagnostic data including month of birth of 436 MS offspring (M – 171, F – 265), deceased in the year 2007 were derived from the Central Statistical Office in Warsaw. Information on previous SOR, UVB, TOCA and AT in Poland in the scattered years (1931–2007) was obtained from the Institute of Meteorology. Results: Longer exposure to SOR and higher level of UVB during maternal gestation were associated with the smaller number of MS offspring; linear regression test: r = –0.598, p = 0.040 and r = –0.587, p = 0.035. TOCA and AT during gestation were not significantly correlated with the number of MS offspring: r = –0.280 (p = 0.830) and r = –0.437 (p = 0.104). However, decreased TOCA during birth month of offspring was significantly associated with the smaller number of children destined to develop MS: r = +0.631, p = 0.028. Conclusions: Longer gestational exposure to SOR and more intense UVB were associated with lower risk of MS in offspring. Reduced risk of the disease was also correlated to decreased TOCA during month of offspring birth.