Building on the results of an initial analysis of risk ranking data collected from a representative group of some 850 Canadian respondents in early 2003, this study assesses a similar set of risk ranking questions applied to a somewhat larger representative group of some 1500 Canadians in late 2005. We also compare the 2003 and 2005 risk rankings. In both surveys, risk rankings for eight food safety issues (bacteria contamination, pesticide residuals, use of hormones in food production, use of antibiotics in food production, BSE (mad cow disease), food additives, use of genetic modification/engineering in food production, fat and cholesterol in food) and six environmental safety issues (water pollution by chemical run-offs from agriculture, soil erosion, GM, herbicide/pesticide resistance, adverse effects of agriculture on biodiversity, genetic modification/engineering, and agricultural waste disposal) were queried. These were ranked by respondents from 1(high risk) to 4(almost no risk) and 5(don't know). The order of questions was randomized across respondents. Attitudinal and demographic information were also collected in each survey. Respondents' risk perceptions did change appreciably for some of the food safety issues in 2005, compared with 2003; there were less changes for environmental safety issues. Pesticide residuals were rated as less of a "high risk" issue in 2005 than in 2003, while the use of food additives was indicated as "high risk" by more respondents in 2005 than in 2003. Econometric analysis based on ordered probit models suggests that women, older respondents and residents of Quebec were still the populations tending to give high-risk ratings in 2005. Comparing the data sets from the two periods suggests that a structural break occurred in several of the risk rankings over the two periods as some subgroups of respondents changed attitudes between 2003 and 2005. For example, men and those with university degrees tended to view pesticide residuals to be more risky in 2005 than in 2003, while those with higher incomes and those living in Quebec were less likely to rate pesticide residuals to be highly risky in 2005 than in 2003. The use of GM/GE as a food safety risk was rated higher in 2005 than in 2003- attitudes to this technology may be hardening. However, BSE was rated lower as a high risk food safety issue in 2005 than in 2003, suggesting that more information and/or effective risk communication may have accompanied the three Canadian BSE incidents that occurred during the time period between the two periods.