The objective of the present study was to determine the effect of feeding fermented earthworm casts (EEC) to layers on egg-laying performance, blood lipid profiles, cecal microflora, and fecal odor removing performance. A total of 200 Hyline Brown layer chicks at 33-week-old were used in this study. They were randomly assigned to two numerically equal groups with 100 replications per treatment for 10 weeks. All the birds were caged individually. The control group was not treated with EEC. The EEC group was treated with top dressing containing 3.5% EEC. The present study revealed that egg production and egg weight were increased after feeding diet containing EEC at the top dressing level. Haugh unit, eggshell thickness, and eggshell breaking strength of EEC group were higher than those of control group. Egg yolk was determined for fatty acid profiling. It was found that EEC group had higher ratio of unsaturated- to saturated fatty acid as compared to control group. Lower ratios of n-6 to n-3 fatty acids were found in the egg yolk of EEC group. Plasma triglyceride and total cholesterol contents were lower in the EEC group. However, high density lipoprotein-cholesterol content was higher in the EEC group as compared to that in control group. The number of cecal Lactobacillus was increased while the population of Escherichia coli and coliform bacteria decreased in the EEC group. Fecal ammonia and hydrogen sulfide contents were lower in the EEC group as compared to those in control group. Taken together, these results suggested that EEC could improve egg production and egg quality. In addition, it could remove odour from laying-hen manure.