Background Incisional hernia is a frequent complication of abdominal wall incision and has a high rate of recurrence. Most of the studies stated that non-absorbable sutures decreased incisional hernia incidences, but some stated otherwise. We aimed to compare the collagen type I/III ratio between monofilament non-absorbable sutures and multifilament absorbable sutures for abdominal fascia closure in Wistar albino rats. Methods Forty rats were divided into four groups. Groups 1 and 3 were sutured with monofilament non-absorbable ( polyvinylidene fluoride ). Groups 2 and 4 were sutured with multifilament absorbable ( polyglycolide ). Then, groups 1 and 2 were euthanized on day 4 (POD 4), while groups 3 and 4 were euthanized on day 7 (POD 7). Samples of fascia (1 × 0.5 cm) were taken for analysis. Collagen I/III ratios were measured using immunohistochemistry staining methods. Results While the expression of collagen I was not significantly different between monofilament non-absorbable and multifilament absorbable at POD 4 and 7 ( p = 0.45 and 0.81, respectively), the expression of collagen III reached a significant level with p -values of 0.0003 and 0.0004 for POD 4 and 7, respectively. Moreover, the collagen I/III ratio was also significantly different between the two groups either at POD 4 (0.88 ± 0.23 vs. 0.53 ± 0.08; p = 0.0003) and 7 (1.77 ± 0.65 vs. 1.03 ± 0.28; p = 0.004). Conclusions Monofilament non-absorbable sutures show a significantly higher collagen I/III ratio than multifilament absorbable sutures for abdominal fascia closure in rats. Our findings imply that the usage of monofilament non-absorbable sutures might have a beneficial effect on decreasing the incisional hernia occurrence.