Sanderson, K. R. and Fillmore, S. A. E. 2012. Slow-release nitrogen fertilizer in carrot production on Prince Edward Island. Can. J. Plant Sci. 92: 1223-1228. The impact of nitrogen management using slow-release fertilizers has not been examined for carrot (Daucus carota L.) production in Atlantic Canada. To assess the effects of such products, we evaluated five slow-release fertilizers over a 3-yr period. Treatments consisted of sulphur coated urea (SCU) (42-0-0), isobutylidene diurea (IBDU) (31-0-0), Nutralene^® (methylene urea) (40-0-0), Sirflor^® (urea formaldehyde) (38-0-0), UFLEXX™ (urea, dicyandiamide, N-(n-butyl) thiophosphoric triamide) (46-0-0) compared with industry standard (ammonium nitrate) (34-0-0). All slow-release fertilizer treatments supplied N at 50 kg N ha^-1 pre-plant. Slow-release fertilizer treatments were compared with the industry standard of 50 kg N ha^-1 pre-plant plus 50 kg N ha^-1 as a top dress. UFLEXX™ increased biological and marketable yield by 7.5 and 18.7%, respectively, compared with the industry standard. Sirflor^® produced the lowest yield. GreenSeeker^® NDVI reading and LECO N were correlated at the mid-season sample. GreenSeeker^® technology has potential as an in-field crop health assessment tool, however, further research is required to develop GreenSeeker^® algorithms appropriate for carrot production in Prince Edward Island.