Comparison of unauthorised absenteeism rates were made between two large textile factories in Isfahan, Iran. The working conditions in the study factory were rather unsatisfactory, unlike the control factory. Comparison showed significantly higher rates for the study factory: the average annual duration per person was 7 days in the study factory versus 2.5 days in the control factory, and lost time percentage was 2.4% in the former versus 0.84% in the control. Inception rate of persons was 0.73 versus 0.48, and point prevalence rates 0.002 versus 0.001, whilst period prevalence rates were 0.016 versus 0.011 for the study and control factories respectively. Examination of the study factory data was made to determine any possible relationship between unauthorised absenteeism rates and age and length of employment. It was found that higher unauthorised rates were found amongst the younger workers, 100% for those age 19 and under, versus 59.6% for those age 50 and over. 9.16% of workers employed for 1--4 years took such leave against 70.14% of those employed for 10 or more years. Only 18.8% of all workers took certified sickness absenteeism and the rate increased with age. It was suggested that worker dissatisfaction toward unsatisfactory working conditions may be expressed in terms of unauthorised absenteeism. In view of the widespread consequences of such absenteeism, it is recommonded that closer attention be paid to improve the quality of working life.