Previous studies have shown that mitochondrial DNA (mtDNA) 5178 adenine/cytosine (5178A) polymorphism, which is one of the haplogroup-specific mutations for mtDNA haplogroup D, was apparently associated with aging and longevity in humans. We genotyped the 5178A in 293 samples representing three age groups (Old, n=95; Young, n=103; and Infant, n=95) from Yunnan Province, China. The distribution frequency of the 5178A in the Old samples (16.84%) is slightly higher than in those of the Young (13.59%) and Infant (15.79%), but the frequency difference between the age groups is far from being statistically significant ( P>0.05). Our results fail to support the suggestion of association between mtDNA 5178A (or haplogroup D) and longevity.