Abstract: Apparatus (10) for measuring skin blood flow includes apparatus (12) for applying a predetermined temperature gradient to a portion of skin, thereby to change the temperature thereat from a first temperature to a second temperature; a single temperature sensing element (14) for measuring a temperature at a selected location near the portion of skin; a control apparatus (20) for operating the apparatus (12) for applying a predetermined temperature gradient, and further for operating the temperature sensing element (14) in first and second operative modes; in the first mode the temperature sensing element (14) measuring a first reference temperature at the selected location, and in the second mode the temperature sensing element (14) being operable to measure a second temperature at the selected location; wherein the second mode, the control apparatus (20) operates the apparatus (12) for applying a predetermined temperature gradient so as to maintain the predetermined gradient between the first and second tempe