Objective To observe the protein expression of c-Jun amino-terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in normal skin and keloid and to explore their influences on the formation of kloid. Methods Keloid tissues and normal skin tissues were collected from 16 keloid resection patients (experimental group) and 10 voluntary plastic surgery patients (control group). In the experimental group, the keloid formation time ranged from 8 months to 10 years; the keloid tissues were collected from the chest in 6 cases, the ear lobe in 4 cases, the perineum in 2 cases, the shoulder in 3 cases, and the abdomen in 1 case; and all keloid tissues were confirmed by pathological examination. In the control group, normal skin tissues were collected from the abdomen in 4 cases, the thighs in 3 cases, the shoulder in 2 cases, and the back in 1 case. Two-step l ine of Envision immunohistochemical staining was performed to observe the expressions of nonphosphorylated and phosphorylated JNK and ERK; Image Pro Plus 4.5 image analysis system was used to measure the integrated absorbance (IA) and to observe the positive staining strength. Results The immunohistochemical staining showed that no obvious expressions of phosphorylated and non-phosphorylated ERK, JNK were observed in the fibroblasts of the control group, and the expressions of phosphorylated JNK and ERK proteins were significantly higher in the experimental group than in the control group (P lt; 0.05). There was no significant difference in the expressions of non-phosphorylated JNK and ERK proteins between 2 groups (P gt; 0.05). Conclusion Activation of ERK and JNK pathways might be involved in formation of keloid.