Increasing evidence suggests that systemic inflammation is associated with many pathophysiological processes including frailty in older adults. We evaluated the relationships between white blood cell subtypes, geriatric assessment, and frailty syndrome and in particular, how they correlate with individual frailty criteria (involuntary loss of weight, low energy or exhaustion, slow mobility, muscle weakness, and low physical activity) in frail older women. There was a significant and positive correlation between the frailty score and neutrophil count, but a significantly negative correlation was found when this score was compared to the lymphocyte count. These associations were significant only for two frailty criteria: poor muscular strength and low physical activity. Further investigation into the role of white blood cell subtypes in ageing and its associated adverse outcomes in older adults is warranted, in particular in the loss of muscular strength and for poor physical activity.