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We give the present day mass functions (PDMFs) of eleven North Hemisphere galactic OB associations. UBV photometry of 16,000 stars were obtained with large-format CCD on the KPNO 0.9, with follow-up classification spectra of the intrinsically bluest stars obtained on the Kitt Peak 4m with the multi-fiber feed Hydra. With these data we were able to classify hundreds of previously unclassified stars, determine their color excesses and revise distances to these associations in order to construct accurate H-R diagrams. These diagrams allow us to compare the massive star population directly from one association to another, and to determine to what extent star formation of a given association was coeval and thus to what extent its PDMF reflects its initial mass function (IMF). We compare our results to IMFs found for other galactic OB associations as well as OB associations found in the LMC and SMC.
