We studied the effect of aging after the full-open stage on auto-catalytic ethylene production and the expression of genes for ethylene biosynthesis and signaling pathway following exogenous ethylene treatment in long-life carnation flowers (Miracle Rouge [MR] and Miracle Symphony [MS]). As exogenous ethylene treatment time increased, auto-catalytic ethylene production increased in the petals of the control flower (White Sim), MR and MS, on Day 0 and 3, but it increased only slightly in the MR and MS flowers on Day 15. The levels of ethylene biosynthesis pathway gene Dc-ACS1 in MR petals on Day 15 following 20 h exogenous ethylene treatment were around 1/10 of those on Day 3. In MS on Day 15, the levels were around 1/5 of those on Day 3. The levels of another ethylene biosynthesis pathway gene, Dc-ACO1, did not differ on both Day 3 and 15 in MR and MS. Levels of ethylene signaling pathway gene Dc-EIL4 on Day 3 were higher than those on Day 15 at corresponding times. These results indicated that aging may affect the expression of Dc-ACS1 and Dc-EIL4, but not the expression of Dc-ACO1, ethylene receptors, and Dc-EIL1/2, 3.