Background: Diabetic foot ulcers are long-term wounds that are marked by persistent inflammation, impaired immune response, bacterial infection, and slowed down tissue repair. The capability of forming biofilms, resisting antimicrobial treatment, and persisting in the wound microenvironment make Pseudomonas aeruginosa an important pathogen in diabetic foot infections. Interleukin-8 (IL-8/CXCL8) is a neutrophil chemoattractant, which could be indicative of excess inflammation and immune dysregulation in chronic infected wounds. Aim: The aim of the study was to assess IL-8 as a biomarker of immune dysregulation, the biofilm burden and delayed healing in diabetic foot ulcer infections caused by Pseudomonas aeruginosa. Materials and Methods: It is an analytical case-control clinical study, which was performed on 120 diabetic subjects who were recruited in the private clinics between the period between January 2026 and April 2026. They were separated into four groups: diabetic foot ulcer patients infected with P. aeruginosa (n = 40), diabetic foot ulcer patients infected with bacteria other than P. aeruginosa (n = 40), culture-negative diabetic foot ulcer patients (n = 20), and diabetic controls with no active ulcer (n = 20). Aseptic collection of wound samples was done to test them against bacteria in terms of culture, identification, antimicrobial susceptibility testing, and biofilm formation. The ELISA was used to measure serum IL-8. Where possible, the IL-8 levels of exudates in wounds were measured in ulcer groups. Clinical variables, inflammatory markers, wound severity and healing progress after four weeks were documented. The statistical analysis involved group comparisons, correlation analysis, regression analysis and ROC curve analysis. Results: The P. aeruginosa group had a significant higher level of serum and wound-exudate IL-8 as compared to the non-Pseudomonas-infected group, culture-negative ulcer group and the diabetic control group. Isolates of P. aeruginosa that are strong biofilm-producing were linked to the highest levels of IL-8. The biofilm optical density, the severity of the wound, CRP, WBC count, NLR, wound size and wound duration were positively correlated with IL-8 levels. There was a negative relation between IL-8 and the decrease in the area of the wound after four weeks. Not only MDR P. aeruginosa infection was linked to significantly higher levels of IL-8 as compared to non-MDR infection. The IL-8 was found to be an independent predictor of delay wound healing. Analysis of ROC curve revealed that IL-8 was a good predictor of delayed healing. Conclusion: There is a close association of IL-8 with immune dysregulation, biofilm burden, antimicrobial resistance, wound severity, and delayed healing of diabetic foot ulcers infected with Pseudomonas aeruginosa. The IL-8 can be employed as supportive biomarker in risk assessment and clinical follow-up of diabetic wounds which are chronic.