A medical apparatus, comprising: an insertion tube (14, 38) having a distal portion (18, 42); at least one ablation electrode (36, 48, 50) disposed on the distal portion (18, 42) for conveying electromagnetic energy to a target tissue during an ablation procedure; a first temperature sensor disposed on the distal portion (18, 42) sufficiently proximate the ablation electrode (36, 48, 50) to detect heat generated in the target tissue during the ablation procedure; a second temperature sensor disposed on the distal portion (18, 42) sufficiently spaced apart from the ablation electrode (36, 48, 50) to be relatively less responsive to the heat than the first temperature sensor; and electronic logic circuitry linked to the first temperature sensor and the second temperature sensor and programmed to compute a temperature differential between respective temperatures sensed by the first temperature sensor and the second temperature sensor when conveying the electromagnetic energy, and to indicate a satisfactory contact status between the ablation electrode (36, 48, 50) and the target tissue when the temperature differential exceeds a predetermined threshold, characterised in that the electronic logic circuitry is programmed to compute a first temperature differential and a second temperature differential when relatively high and low flows of coolant are applied to the ablation electrode (36, 48, 50), respectively, wherein the electronic logic circuitry is programmed to indicate an unsatisfactory contact status between the ablation electrode and the target tissue when a difference between the first temperature differential and the second temperature differential fails to exceed the predetermined threshold. an insertion tube (14, 38) having a distal portion (18, 42); at least one ablation electrode (36, 48, 50) disposed on the distal portion (18, 42) for conveying electromagnetic energy to a target tissue during an ablation procedure; a first temperature sensor disposed on the distal portion (18, 42) sufficiently proximate the ablation electrode (36, 48, 50) to detect heat generated in the target tissue during the ablation procedure; a second temperature sensor disposed on the distal portion (18, 42) sufficiently spaced apart from the ablation electrode (36, 48, 50) to be relatively less responsive to the heat than the first temperature sensor; and electronic logic circuitry linked to the first temperature sensor and the second temperature sensor and programmed to compute a temperature differential between respective temperatures sensed by the first temperature sensor and the second temperature sensor when conveying the electromagnetic energy, and to indicate a satisfactory contact status between the ablation electrode (36, 48, 50) and the target tissue when the temperature differential exceeds a predetermined threshold, characterised in that the electronic logic circuitry is programmed to compute a first temperature differential and a second temperature differential when relatively high and low flows of coolant are applied to the ablation electrode (36, 48, 50), respectively, wherein the electronic logic circuitry is programmed to indicate an unsatisfactory contact status between the ablation electrode and the target tissue when a difference between the first temperature differential and the second temperature differential fails to exceed the predetermined threshold.