Scouring around bridge piers is known as one of prominent factors causing destruction in bridges. This phenomenon is commonly observed due to collision of flow with bridge piers, 3-dimensioanl variation in local flow pattern, increased stress around piers and as a consequence creating scour hole in the vicinity of bridge piers. Exploitation of conical and combined piers rather than cylindrical type would decrease the scouring erosion. The advantages of conical piers over cylindrical piers include decreasing in piers cross-sectional area and increasing the width of river underneath the water free-surface. Due to this fact, a large amount of flow would rapidly pass through the above part reducing the shear stress at the bottom and subsequently decline the scouring. Moreover, compared to cylindrical pier, there would be lower dynamic pressure at conical pier upstream providing a weak downward flow in front of the conical pier. Additionally, the slope of conical pier is considered as a resistant factor against increasing downward velocity. Current study experimentally investigates the effects of bridge piers geometry on scouring by causing transition from cylindrical piers to conical and combined cylindrical-conical piers. Model experimentation has been conducted in the civil faculty hydraulic lab at Isfahan university of technology with 0.6m width, 0.7m height and 9.5m length. Experiments have been carried out using 13 different piers including the cylindrical, the conical and the combined shapes and also changing the average diameter of bed stone gradation (0.74mm, 1.75mm) with specific gravity of 2.65. In addition, this study is primarily aimed at studying the effects of changes in piers diameter (50mm, 60mm, 70mm) and angles of conical and combined piers along with diverse hydraulic circumstances including discharge changes (36, 43, 50 lit/s), variations of flow intensity (0.7, 0.8, 0.9), velocity and depth on scouring around conical and combined piers. Present outcomes reveal that exploitation of conical and combined piers rather than cylindrical ones, decreases the scouring amount up to 20%. The conical pier shape radically affects the scouring depth around the piers in the case of conical and combined piers with the angle higher than 5 . The piers would perform as the conical types, provided that the relative conical section height is higher than 2, but Otherwise they perform as cylindrical piers. Comparing to cylindrical and combined piers, the conical shape shows better performance at the flow intensity of 0.9. The topography observations around the conical and combined piers denote that the length and the width of scouring hole and also the sedimentation deposing volume are respectively 35%, 40% and 30% less than the cylindrical piers. Employing the conical and combined piers not only diminishes the scouring depth nearly up to 20%, but also delays the scouring development time. The present investigation proposes empirical formulae calculating the scouring depth around cylindrical, conical and combined piers.