Delta crystalline form of perindopril L-arginine salt (I) having X-ray powder diffraction peaks measured using a diffractometer with a copper anticathode and expressed in terms of Bragg's angle 2 theta values as given in the specification, is new. Independent claims are included for: (1) the preparation of delta crystalline form of (I); and (2) a composition comprising an active agent and the delta crystalline form of (I) in combination with carriers. ACTIVITY : Cardiovascular-Gen; Hypotensive; Cardiant; Vasotropic. MECHANISM OF ACTION : Angiotensin I converting enzyme inhibitor.본 발명은 X-선 분말 회절 다이어그램을 특징으로 하는, 하기 화학식 (I)의 화합물의 델타 결정형, 및 이의 약제로서의 용도에 관한 것이다: