Objectives: To describe the variation of axial length in patients undergoingcataract surgery. Study design: A retrospective case series. Place and duration of study: At OpthalmologicalDepartment, Allied Hospital, PMC, Faisalabad from May 2006 to June 2007. Patients and methods: The axial lengthof 566 patients who were admitted for cataract surgery were measured with A. scan (Axis II, Quantel). The elevenpatients with age below 15 years and above 90 years and with history of trauma, corneal scarring were excluded. Sothere were 555 patients for this study. A careful history of diabetes mellitus, hypertension, trauma, previous history ofsurgery, glaucoma and uveitis was taken, and slit lamp examination, tonometry, pupillary reactions, perception andprojection of light was done. The data collected was entered in specially designed Performa. An average of tenreadings of axial lengths with A-Scan for each patient was taken. Results: Out of 555 patients, there were 350 male(63.06%) and 205 female (36.94%) patients. There were 250(45.05%) patients having age between 46 to 60 years.There were 27(4.86%) patients having age between 15 to 30 years and the same number 27(4.86%) of patients wasseem having age between 76 to 90 years. The most of the patients 273(49.18%) had axial length between 23mm to25 mm. There were only 3 patients with axial length between 29.01 to 31 mm. There were a significant number ofpatients, 230(41.45%) having axial length between 21.01 to 23mm. Conclusion: The biometry depends upon axiallength, kratometry and anterior chamber depth. Most of the formulae supposed for IOL calculations depend upon onlytwo factors, the axial length and the keratometry. In our community, short and long eyes are very rare and so SRK-Tformula for IOL calculations provides satisfactory postoperative results. The axial length carries more importance asits variation causes a gross change in IOL power and postoperative refractive errors.