Objective of this research was to study on quality of Nham-pla inoculated with single or mixed cultures compared with Nham-pla without inoculum. Pure cultures used in this study were isolated from Pla-som or somfug, consisted of lactic acid bacteria in homofermentative group, Pediococcus pentosaceus TISTR 423, Lactobacillus pentosus TISTR 853 and L. plantarum TISTR 854, and heterofermentative group, L. fermentum TISTR 937, and yeast Candida sake (IFRPD). Acid production and pH changing during Nham-pla fermentation with homofermentative lactic acid bacteria was studied. Nham-pla with inoculum of L. plantarum had the lowest pH and the highest acidity among Nham-pla inoculated with other cultures (p LT= 0.05), so it was selected to used in quality study of Nham-pla inoculated with single or mixed cultures compared with Nham-pla without inoculum (control). Nham-pla inoculated with single L. plantarum and mixed culture, L. plantarum and L. fermentum or L. plantarum and C. sake (IFRPD), had higher hardness and L* values and had lower a* values than control. Nham-pla inoculated with L. plantarum had springiness and overall liking score more than control but not significantly different from Nham-pla inoculated with mixed cultures. Therefore, L. plantarum in single or mixed cultures can be used for reducing fermentation time and improving Nham-pla quality. Summaries