Introduction: The prototypical psoriasiform tissue pattern is psoriasis, both clinically and histopathologically. However, it should be distinguished from other psoriasiform dermatoses. Objective: This study aimed to determine the expression of Ki-67 immunohistochemically in psoriasis and psoriasiform dermatoses for diagnostic reasons. Material and Methods: Between January 2020 and January 2021, a cross-sectional study was conducted on the paraffin blocks of 22 psoriasis and 22 psoriasiform dermatoses patients. Four-micron sections were cut from formalin-fixed paraffin-embedded tissue from each biopsy specimen. Hematoxylin and eosin staining was used to colour the initial sections. Additionally, Ki-67 immunohistochemistry was performed. Results: Mean value of KI-67 expression was highly significant in psoriasis (94.4 ± 11) versus (21.1 ± 5.7) than in psoriasiform dermatoses (P value < 0.001). Conclusion: Ki-67 expression was shown to be significantly elevated in psoriasis compared to the other types of dermatoses studied.