To study the technical difficulties using the MONARCH II injector, intraoperative incidents, postoperative astigmatism.Retrospective study which included 135 eyes with cataract who underwent cataract surgery between March 2002-August 2003. The surgical intervention consisted of lens extraction by phacoemulsification technique and IOL implantation with the MONARCH II injector. We recorded the following parameters: problems during the loading of the IOL in the cartridge, difficulties during the implant, problems due to the damage of the IOL during the passage in the cartridge, IOL centration in the capsular bag, induced postoperative astigmatism.We had no major difficulties using this type of injector. We did not recorded important differences between the hydrophobic and hydrophilic IOLs. We had a number of 17 intraoperative incidents (12.6%). We met the following intraoperative incidents: the last haptic capture in the tunnel of the cartridge in 5 cases (3.7%), small marks on the optic surface left by the tip of the injector in 3 cases (2.2%), the leading haptic stuck on the optic surface in 2 cases (1.4%), breaking of the last haptic (multi-piece IOL) in 1 case (0.7%), the turning up side down of IOL during unfolding (hydrophilic IOLs) in 6 cases (4.4%). Postoperative astigmatism was less than 1D cylinder in 88% of cases.The IOL implantation using MONARCH II injector is easy and doesn't need learning curve. The technique is superior compared with forceps implantation (especially for acrylic hydrophilic IOLs). No significant differences between implantation of acrylic IOLs. IOL centration was good. The design of the injector tip preserved optic surface and haptic from damage. The conical tip of the cartridge didn't change the architecture of the corneal wound. The postoperative astigmatism was small.