The rates of CH3NHNO2 and (CH3)(2)NNO2 reaction with OH radicals were determined relative to CH3OCH3 and CH3OH at 298 +/- 2 K and 1013 +/- 10 hPa in purified air by long path FTIR spectroscopy, and the rate coefficients were determined to be k(OH+CH3NHNO2) = (9.5 +/- 1.9) x 10(-13) an k(OH+(CH3)2NNO2) = (3.5 +/- 0.7) X 10(-12) (2 sigma) cm(3) molecule(-1) s(-1). Ozone was found to react very slowly with the two nitramines, k(O3+nitramine) < 10(-21) cm(3) molecule(-1) s(-1). Product formation in the photo-oxidation of CH3NHNO2 and (CH3)(2)NNO2 was studied by FTIR, PTR-ToF-MS, and quantum chemistry calculations; the major products in the OH-initiated degradation are the corresponding imines, CH2=NH and CH3N=CH2, and N-nitro amides, CHONHNO2 and CHON(CH3)NO2. Atmospheric degradation mechanisms are presented.