A four-year-old sexually intact male dog and a seven-year-old sexually intact female dog presenting with heavy tick infestation were tentatively diagnosed with tick paralysis. Both dogs died due to respiratory failure. A number of ticks were observed in the head, ears, neck, trunk, and limbs of each dog. In these cases, a presumptive diagnosis of tick paralysis could be based on the presence of a species of tick known to cause paralysis combined with the absence of any other disease previously. Most ticks were identified as Haemaphysalis longicornis according to morphological features. Tick paralysis in dogs has rarely been reported in Korea.