The main All Share Price Index fell 0.25 percent (14.96 points) to 6,074.42, while the more liquid Milanka index fell 0.
64 percent (33.60 points) to 5,229.16.
Turnover was 526 million rupees, according to stock exchange provisional figures.
Commercial Bank once again topped the day's turnover with 940,200 shares traded and closing at 100 rupees, up 10 cents.
There was one crossing or off-market private deal of 550,000 Commercial Bank shares at 100 rupees each.
Tess Agro, which went up sharply Thursday on speculation, was the most actively traded stock Friday, closing at 4.
50 rupees, down 30 cents with 16 million shares changing hands.
Bartleet Religare Securities said in a report that the stock's rise over 20 percent Thursday indicated that the Sri Lankan market is "still the place to be for the speculator.
"
It asked whether Tess Agro's rise could be the beginning of "the speculator rally that we have been waiting for" and whether other shares would follow in its footsteps.
Muller and Phipps (Ceylon) was the second most actively traded stock, ending at 2.
80 rupees, down 10 cents, with over 5.
8 million shares done.
HVA Foods was also actively traded, closing at 38.
70, up 20 cents.