The general population is ageing. In the UK the estimated number of people aged over 65 years is expected to double to 19 million by the year 2050. The NHANES III study estimated that the prevalence of stage 3 CKD in the United States among people of this age group without hypertension and diabetes is approximately 11%. Older people with CKD are different to their younger counterparts. Their risk of progression to end stage kidney disease (ESKD) is comparatively low, and risk of death due to cardiovascular co-morbidities high. Age is therefore a potentially important factor in predicting outcomes in CKD and dialysis. In addition, the potential misclassification of CKD stages, which are based on calculated eGFR, may occur in older people due to interaction between muscle mass and creatinine based equations. This can increase the burden on clinical services. Indeed, the benefits of dialysis in older people are not clear compared to conservative care (CC). The aims of this thesis were to compare the clinical phenotype and outcomes in patients of different ages within a referred CKD cohort, to establish whether dialysis has a survival advantage over conservative care in older people, and to compare the performance of the MDRD and CKD-EPI equations in defining CKD stages in different age groups. The key findings were as follows: (1) The risk associated with CKD in older age shows significant variability between different primary renal diseases. The hazard ratio (HR) for death in glomerulonephritis patients aged >75 years compared to those aged 75 years) was -1.10, 0.47, 1.76 and 2.89 ml/min/1.73m.sq. respectively. In conclusion, age is important in estimating GFR from serum creatinine values, and its consideration may provide greater prognostic accuracy in individual primary renal diseases. Age does not appear to be a barrier to the benefits of dialysis for ESKD.