Although the 2008 food price crisis presumably plunged millions of households into poverty and food insecurity, the real impact of the crisis has rarely been documented using field data. Our objective was to assess the consequences of this crisis for household food insecurity and dietary diversity in urban Burkina Faso. Two cross-sectional surveys were conducted among randomly selected households in Ouagadougou in July 2007 (n = 3017) and July 2008 (n = 3002). At each round, food insecurity assessed by the Household Food Insecurity Access Scale (HFIAS), the Dietary Diversity Score of an index-member of the household (IDDS = number of food groups consumed in the last 24 h), and food expenditure were collected. Food prices of the 17 most frequently consumed food items were recorded throughout the study area. Food prices at local markets increased considerably between 2007 and 2008, especially those of fish (113%), cereals (53%), and vegetable oil (44%), increasing the household monthly food expenditure by 18%. Thirty-three percent of households were food secure in 2007 and 22% in 2008 (P = 0.02). Individuals consumed fewer fruits and vegetables, dairy products, and meat/poultry in 2008 than in 2007 (mean IDDS = 5.7 ± 1.7 food groups in 2007 vs. 5.2 ± 1.5 in 2008; P < 0.0001). Differences in IDDS and HFIAS between the 2 y were even more marked after adjustment for confounding factors and food expenditure. Food security and dietary diversity significantly decreased between 2007 and 2008, whereas food prices increased. Households increased their food expenditure, but this was not sufficient to compensate the effects of the crisis.