Borage (Borago officinalis L.) seed oil is rich in gamma-linolenic acid (GLA) and it used in the pharmaceutical industry. Continued production of borage as an alternative crop in North Dakota may depend on seed production consistently producing or exceeding the market threshold of 22% GLA. Delayed seeding could increase the GLA content of borage, which would shift flowering and seed development into late summer when temperatures are cooler. The study objective was to determine the influence of seeding and flowering date on composition of borage seed oil. A field study was conducted at Carrington, Langdon, and Prosper, ND in 2002 and 2003. The study was a randomized complete block with four replicates and two factors arranged in a split-plot design. The main plot was seeding date and the subplot was flowering dates. Seeding dates were targeted for 1 May (D1), 15 May (D2), 30 May (D3), and 15 June (D4). Individual borage seeds (30 to 40 per plot) were collected from flowers producing seeds from early, mid, and late flowering dates at each seeding date. At the northern Langdon location in 2002, seed development that occurred in late summer (D3 and D4), when temperatures were cooler, showed higher GLA levels (24%) than seeds that developed during the warmer temperatures of mid-summer (D1 and D2). These responses were significantly different among station-years. In 2003, the highest GLA content in Langdon was 19.8% for D4. In 2003, GLA was low at all locations and dates since the summer was warm. Results from the more southern locations, Carrington and Prosper, in the cooler growing season of 2002 did not show seeding date influence on seed GLA content, however, a slight tendency for increased GLA content in later seeding dates was observed.