Magnetic recording tape

A magnetic recording tape comprising a polyethylene terephthalate substrate and a mangnetic material-containing layer closely adhered onto the substrate, characterized in that said polyethylene terephthalate substrate satisfies the formula:

• 0.051H.sub.1 -0.59A+0.14.DELTA.n+0.0015(H.sub.2 -66.67).sup.2 +50.92.ltoreq.20
• wherein A is the average particle size of the polyethylene terephthalate crystals as determined from the half height width by X-ray diffractometry, and H.sub.1 is the average number of projections present in a unit area of 1 mm.sup.2 on the surface of the substrate, which projections have a height falling within the range of from 0.27 to 0.53 micron, H.sub.2 is the average number of projections similar to H.sub.1 above but having a height falling within the range of from 0.54 to 0.80 micron, rather than 0.27 to 0.53 micron, and .DELTA.n is the birefringence of the substrate, said surface projections being formed by interesterifying dialkyl terephthalate and ethylene glycol in the presence of calcium acetate as an ester-interchange catalyst, followed by polycondensing the interesterified product, thereby to precipitate particles of calcium compounds represented by the following formula during the formation of said tape ##STR2## wherein n is an integer of from 0 to 3.