This was due to rising administration and sales costs.
Portland's pretax profit fell to 171 million shillings from 376.5 million in the same period in 2012.
The firm, which also operates in Uganda, said its total revenues rose 0.4 percent to 4.57 billion shillings, while cost of sales increased 1.4 percent to 3.25 billion.
Portland, Kenya's No. 3 cement producer, said its administration and selling expenses rose to 1.26 billion shillings from 1 billion, while earnings per share dropped to 2.03 shillings from 3.68 shillings.
It did not recommend payment of a dividend.