We measured gross primary productivity (GPP) in vitro and GPP and net community production (NCP) in situ on four cruises to the Hawaii Ocean Time series (HOT) station ALOHA during 2002--2003. In vitro GPP, determined by 18O labeling, yielded integrated production (0--100 m) that was on average 1.5 times the 14C integrated production. Mean integrated productivity from two winter and two summer cruises was 575 mg C m-2d-1 and 930 mg C m-2d-1, respectively. In situ GPP, determined from the triple-isotope composition of dissolved O2, averaged 910 mg C m-2d-1 in the winter and 1225 mg C m-2d-1 in the summer/fall, with an uncertainty of ¿40%. The NCP/GPP ratio, determined using O2/Ar gas ratio and oxygen isotope measurements, was around 0.1 in the summer, close to the canonical f-ratio for the open ocean, indicating station ALOHA is a net autotrophic system during summer months. The consistently higher gross carbon production measured by the in situ method, which integrates production over the ~2-week residence time of O2 in the mixed layer, suggests that aperiodic bursts of production contribute significantly to time-averaged mean productivity at station ALOHA.