OBJECTIVE: The aim of this study was to determine the longitudinal associations between dietary diversity score and serum lipid markers in a five-year follow-up period in Japanese workers. METHODS: This study included 745 participants aged 20-60 years in 2012-2013 without dyslipidemia at baseline who participated at least once from 2013 to 2017. Dietary intake was assessed using a food frequency questionnaire, and dietary diversity score was determined using the Quantitative Index for Dietary Diversity. Principal component analysis was used to determine three dietary patterns: healthy, western, and sweetener. Lipid markers including total cholesterol, triglycerides, LDL-cholesterol, HDL-cholesterol, and non-HDL-cholesterol were measured. Generalized estimating equations were used for calculating the cumulative mean of lipid profiles in the follow-up period according to the dietary diversity score at baseline with control of confounding factors. RESULTS: Higher dietary diversity score was inversely associated with serum concentrations of LDL cholesterol (p for trend = 0.028), triglycerides (p for trend = 0.029), and non-HDL cholesterol (p for trend = 0.026) in women. The associations except for the association with serum triglycerides were robust after additional adjustment for three dietary patterns (healthy, western, and sweetener). The association with serum triglycerides disappeared after additional adjustment for a healthy pattern. There was no significant association between dietary diversity and dyslipidemia in men in the follow-up period. CONCLUSIONS: This study suggests that dietary diversity is beneficial for lipid profiles in Japanese female workers.