Harvard doesn't take American Express.

And it doesn't take Visa or Mastercard either when it comes to tuition payments.

Indeed, despite a growing trend in higher education to allow students and parents to put college payments on plastic, Harvard has quietly but firmly maintained a policy prohibiting tuition payment by credit card.

The position, according to Director of Student Financial Services Nona D. Strauss reflects little more than a desire to uphold fairness and the law, and not any desire to keep customers from enjoying the benefits increasingly lavished on some card holders based on their level of purchases.

Those benefits can range anywhere from free airline tickets on U.S. air carriers to points redeemable for free dining or hotel stays.

Strauss says most of the people she comes in contact with who want to use a credit card hope to capture those benefits--to nab what could be 31,000 extra frequent-flier miles for a year of schooling or a 2 percent cash back on purchases. (Hey, $620 makes a difference.)

But allowing some people to pay by plastic would have deleterious effects on the entire student population, Strauss says. Because credit card companies charge a nominal percentage fee on every purchase, Harvard would lose a small portion of each student's tuition paid by credit, thereby forcing the College to impose a flat fee across the entire undergraduate population to recoup the losses.

Strauss says that although many of the people who want to pay by credit card are willing to absorb the fee associated with their own charges, government banking regulations prohibit the selective assessment of such fees.

Rather than violate the law or assess every student a flat fee, Harvard simply avoids the issues altogether--limiting forms of payment to cash, checks or electronic wire transfers.

But for those students and parents who need more flexibility in paying Harvard's admittedly large tuition bills, Strauss says the College offers a monthly, interest-free payment plan that she says can be considered a significantly cheaper stand-in for a credit card.

Among the Ivy League, at least, Harvard's policy with regard to credit cards is still in the majority--only Columbia permits charge-able tuition.

Throughout much of the country, however--and especially among larger public institutions--the use of credit cards to pay for tuition has become big business.

Many colleges cite large savings from moving to a more electronic form of payment--and some even see it as a convenient service that helps attract students.

But after fours years of allowing plastic, Tufts University in Medford took itself out of the credit card market in 1997, citing mounting losses from the fees that credit card companies skim from every tuition payment.

"The costs were quite substantial and far in excess, from a corporate perspective, of any benefit that the institution could derive," says Thomas S. McGurty, vice president for finance and treasurer at Tufts. "I think many people, quite frankly, were using [the payment option] to realize frequent flier miles. It just didn't make economic sense for the institution as a whole."

Still, the Harvard Extension School--the only school at Harvard to accept credit cards for tuition payments--says the benefits to students continue to outweigh the costs.

The response to the option, according to Manager of Student Financial Services Christine M. Gravell-Santos, has been astounding.

She says roughly 75 to 80 percent of all students at the extension school now pay for their courses with credit cards. And although the school does pay a fee to offer the service to students, Gravell-Santos says the policy is particularly beneficial to the extension school students--many of whom work part time in order to take class and rely on credit to help finance their education.

And in case Jerry Seinfeld is wondering, Gravell-Santos says that as of two years ago, the extension school does take American Express.