SUMMARY: Background: O RhD-negative (ONeg) red cells can be used in an emergency for recipients of other blood groups. Matching supply and demand is currently a challenge; therefore, any service redesign, using more remote blood fridges, must consider ONeg red cell availability. Objectives: To identify whether the number of fridges stocking emergency ONeg units correlates with use and wastage. Methods: The number and distribution of ONeg red cells was requested from the hospitals in South West England. For NHS Hospitals, comparison was made with ONeg National Health Service (NHS) organisation - NHS Blood and Transplant (NHSBT) issues (ONeg as a proportion of all red cells), wastage and the proportion of ONeg units given to ONeg patients (ONeg-to-ONeg use). Correlations were performed using Spearman's rank correlation coefficient. Results: Of the 23 hospitals, 21 responded. Four hundred and forty three ONeg units were held across the region - 56% as stock and the remaining as emergency units. ONeg issues increased with the number of fridges holding emergency units (ρ=0·48, significance 0·046). No correlation was found between the number of fridges and ONeg wastage or ONeg-to-ONeg use. A longer unit shelf life on rotation back to stock was associated with lower wastage (ρ=-0·597, significance 0·009). Conclusions: Although there was a weak correlation between fridge numbers and overall percentage ONeg use, there was no correlation with ONeg wastage. © 2014 British Blood Transfusion Society.