In order to assess the utility of fluid catalytic cracking (FCC) for upgrading bio-oils derived from the hydro thermal liquefaction (HTL) of microalgae, 10 wt% HTL algae bio-oil was blended with heavy vacuum gas oil (HVGO) and co-processed in a Short Contact Time Microactivity unit. Compared to pure HVGO, addition of 10 wt% HTL algae bio-oil caused a modest decrease in conversion at all catalyst-to-oil ratios, with marginally increased catalyst coking being observed for the blended feed. The resulting liquid products contained a higher percentage of decant oil (DCO) and a lower percentage of gasoline than those obtained when HVGO alone was employed as feed, the amount of light cycle oil (LCO) being similar in both cases. Nearly complete heteroatom removal from the blended feed was observed, the extent of denitrogenation achieved being particularly note-worthy given that nitrogen-bearing compounds are much more abundant in algae-derived bio-oils than in HVGO. Overall, results indicated that while 10% bio-oil in HVGO would be economically unfavorable when compared to upgrading HVGO alone, it is nonetheless amenable to co-processing and may offer advantages over pyrolysis oils as an FCC feed. Finally, additional means to optimize the commercial application of this process are proposed based on techno-economic considerations.