The study was conducted to determine the effect of calcium (Ca) supplementation in the diets of old layers using different Ca sources and levels on their production performance and egg quality. One hundred 50-week old layers were randomly distributed to five treatments following a completely randomized design: 1) basal diet (control); 2) basal diet + 1% Ca source A; 3) basal diet + 1.5% Ca source A; 4) basal diet + 1% Ca source B; and 5) basal diet + 1.5% Ca source B. Each treatment was replicated 20 times with an individually caged layer per replicate. The feeding period lasted for 16 weeks. Results showed that the addition of 1% and 1.5% Ca from different sources other than limestone (grits and fine) did not significantly affect the performance of the old layers in terms of body weight gain, livability, feed consumption, feed efficiency and percent egg production. However, significant effect was only observed on egg quality parameters in layers fed with 1% and 1.5% additional Ca – heavier eggs laid, thicker shells and lesser number of defective eggs. The added component of the Ca supplements improved Ca absorption resulting in improved egg quality. It is also implied that 5.15g of Ca per day is tolerable; above this level depresses egg production. Income over feed cost was higher for layers fed with 1% additional Ca supplementation followed by diets with 1.5% additional Ca source.