Objective: To analyze differences in affected upper limb functionality (grip strength, digital pinch grip, sensitivity, and manual dexterity) in a population with breast cancer, and the prediction of these factors in perceived disability. Design: Cross-sectional, quantitative, non-randomized, descriptive study. Setting: Eurovillas Physiotherapy and Pilates Clinic, Specialty Center of Torrejón de Ardoz, in Madrid; and Rosae, an association of women affected by breast cancer, in Valdepeñas, Spain. Participants: A total of 42 women diagnosed with breast cancer, with neuropathic symptoms in the upper limb after receiving chemotherapy, radiotherapy, or hormone therapy. Main Measure: A 40-minute assessment, including the collection of sociodemographic data and administration of the following scales: dynamometry, Spanish Nottingham Somatosensory Assessment Stereognosis Scale, Moberg Pick-up Test, Jebsen & Taylor Hand Function Test, Disability and Shoulder Pain Index (SPADI), pinch dynamometry. The statistical analysis was performed with SPSS 29.0 software. Student's t-tests were used for the group comparison, and the effect size (Cohen's d) was analyzed. An analysis of variance was employed for the linear regression analysis between disability and functionality of the upper limb, considering p50 years (p=0.002). Significant differences were also found in total affected hand disability (F=6.472; D=−0.534) between the group of active and passive women (p=0.015) and in total SPADI time (p=0.026), as well as in mean digital pinch grip (F=5.419; D=.467) between the group of women with surgery ≤4 years and women with surgery >4 years previously (p=0.027). Regression analysis revealed that grip strength, digital pinch strength, hand function, and surface sensitivity are predictor variables in 25.7% of perceived shoulder pain and disability cases. Conclusions: Breast cancer causes motor and sensory disorders in the affected upper limb and in the daily life of those with the disease, triggering disability and reduced quality of life.