Purpose The multidisciplinary RIB-IMPROVE rib fracture guideline was implement at Whangārei Hospital with the aim of improving the care of patients with rib fractures. The aim of this study was to assess the impact of this on the management and outcomes of patients. Methodology A single centre retrospective audit was performed comparing patients with rib fractures pre and post the implementation of the RIB-IMPROVE guideline. The primary outcome of interest was the pneumonia rate. Patients were excluded with an abbreviated injury scale score >2 in the head or abdomen. Binomial logistic regression for pneumonia using clinically plausible risk adjustment variables as fixed effects was performed. Results 418 patients were identified; 241 in the pre-guideline and 177 in the post-guideline group. There was no difference in age, gender, ethnicity, number of rib fractures, injury severity score (ISS), or local anaesthetic block placement. The pneumonia rate was 13% vs 7% comparing the pre- and post-guideline groups, respectively. After adjustment for age, gender and injury severity score the relative risk of developing pneumonia was 0.52 comparing the post- with the pre-guideline group (p 0.038). Although a trend towards improvement was seen in all secondary outcomes there was no statistical difference in the LOS, 30-day readmission rate or 30-day mortality rate. Conclusion: This study found that after implementation of the RIB-IMPROVE guideline at Whangārei hospital the risk of pneumonia was decreased by almost half. A trend towards improvement was seen in all secondary outcomes. This study highlights the effectiveness of a multidiscipline guideline in the management of patients with rib fractures.