Primary muscle hydatidosis is very rare, accounting for less than 1% of hydatid cyst locations. Clinical symptoms are insidious and non-specific causing a frequent delay in diagnosis. Intramuscular hydatid disease can cause a variety of diagnostic problems, especially in the absence of typical radiologic findings. We report the observation of an 82-year-old man consulting for inguinal tumefaction with radiological exploration suggestive of hydatid cyst of the adductors muscles. Magnetic resonance imaging (MRI) is helpful in diagnosis, since it reveals a very suggestive aspect and demonstrates the relationship between cysts and adjacent structures. Treatment of muscle echinococcosis is based on surgery, which is curative and incurs a low risk of local relapse.