Stroke often leads to abnormalities in muscle tone, posture, and motor control that may compromise voluntary motor function, thus affecting the motor control required for maintaining the synergy of both peripheral and respiratory muscles. To evaluate respiratory muscle strength, pulmonary function, trunk control, and functional independence in patients with stroke and to correlate trunk control with the other variables. This was a cross-sectional study of patients diagnosed with stroke. We assessed respiratory muscle strength, trunk control as assessed by the Trunk Impairment Scale, spirometric variables, and the Functional Independence Measure. Forty-four patients were included. Pulmonary function and respiratory muscle strength were significantly lower than predicted for the study population, and the mean Trunk Impairment Scale score was 14.3 points. The following significant correlations were found between the variables: trunk control vs. maximal inspiratory pressure (r = 0.26, p < 0.05); trunk control vs. forced vital capacity (r = 0.28, p < 0.05); trunk control vs. forced expiratory volume in one second (r = 0.29, p < 0.05), and trunk control vs. the Functional Independence Measure (r = 0.77, p < 0.05). The present study showed that respiratory muscle strength, pulmonary function, functional independence, and trunk control are reduced in patients diagnosed with stroke.