Background: PD-L1 expression as detected by immunohistochemistry (IHC) is significantly lower in colorectal cancers (CRC) when compared with lung cancer or other types of cancer. We explored if mutations in the RAS/RAF gene family, TP53 or PIK3CA can define a subgroup of CRC that express PD-L1. Methods: Tissue samples collected from 107 patients with CRC were studied for the expression of PD-L1 using clone SP142. The same samples were also tested for mutations in NRAS, KRAS, HRAS, BRAF, TP53, and PIK3CA using Next Generation Sequencing (NGS). Results: Of the 107 CRC samples only 15 (14%) showed PD-L1 positive tumor cells (≥1%) and 8 of the 15 (7.5% of total) had PD-L1 in ≤5% of tumor cells. Detected mutations in these samples were as follows: TP53 65%, KRAS 49.5%, PI3KCA 22.5%, NRAS 5%, HRAS 1%, and BRAF 17%. There was no correlation between PD-L1 expression and mutation status in any of the RAS/RAF genes. There was also no correlation between TP53 mutation and PD-L1 expression. This was true irrespective if PD-L1 expression is considered as a continuous variable or when cut-off points of 5%, 20%, or 50% were used. However, patients without any mutation in RAS or TP53 had significantly (P = 0.005) more expression of PD-L1 when cut-off point of 5% is used. This remained true if PD-L1 expression is considered as a continuous variable (P = 0.04). There was no correlation between PIK3CA and PD-L1 expression. Conclusions: PD-L1 expression is significantly more common in CRC that lack mutations in RAS or TP53. PD-L1 expression is detected in 31% of patients with wild-type RAS/TP53 as compared with 12% in patients with RAS/TP53 mutations (P = 0.04). If a cut-off point of 5% is used, 31% of RAS/TP53-wild-type CRC were positive for PD-L1, while only 6% of RAS/TP53- mutant CRC were positive for PD-L1 (P = 0.005). This suggests that in CRC without RAS/TP53 mutation, the PD-L1 may play a more important role in oncogenesis. Exploring immunotherapy in this group of CRC patients might be justified.