1178 N. Highland St., Arlington. 528-8460.

Hours: Lunch, 11 a.m. to 2:30 p.m. Monday through Saturday; dinner, 5 to 10 p.m. Monday through Thursday; 5 to 11 p.m. Friday and Saturday; closed Sunday.

Atmosphere: Completely casual.

Reservations: Not necessary.

Price range: from $4.95 combination platters to $7 shrimp dinners.

Credit cards: American Express, Carte Blanche, MasterCard, Visa.

Special facilities: wheelchair accessible (except bathrooms); booster seats; street parking; live entertainment.

El Mariachi is off Wilson Boulevard in the heart of Arlington, near a chain store, scores of other ethnic ma and pa restaurants and an off-beat, two-story dance studio.

First impressions of this 48-seat family restaurant weren't encouraging: a nondescript exterior, velvet matte pictures on interior walls and an otherwise frumpy Cisco Kid decor. The linen tablecloths and paper napkins suggested this is a house that doesn't know where it's going.

But the restaurant's strength is not its decor. Things got off to a good start with a smiling hostess attending to us immediately.

El Mariachi has a good assortment of beverages, including imported beer ($1.75) and domestic beer ($1.25). The children had a choice of frosty sodas (70 cents), and several adults shared a large pitcher of sangria ($6), which was fairly choking with tasty fruit.

Two baskets of warm corn chips and dishes of spicy hot red sauce kept us busy while we listened to an unobtrusive guitarist singing entertaining Hispanic tunes.

We finished the two baskets of chips and were working on a third when an excellent and creamy guacamole dip ($3.75) arrived. Our waitress apologized for being out of our hongos ($3.50) a thick, soupy mixture of chili sauce and mushrooms, and provided us with a small, free dish of what was left of this delicious dip in the bottom of the pot.

Salads come with entrees and are of good size and variety, being especially sweet because of a mustard and vinegar dressing -- a perfect contrast before the arrival of our hot entrees.

Our less daring diner chose the standard Mexican fare: tacos, enchiladas and burritos from the "Make Your Own Combination" entree ($4.95). Any three items were more than enough for an adult and were plenty for two youngsters to split.

Other combination platters are $5.50 and come with the same three selections and generous portions of rice and refried beans. The beans were the creamiest and smoothest we've had in the Washington area.

The big hit of the evening, however, was a fairly rare dish in our area, mole poblano. It's an authentic Mexican creation featuring two large chicken pieces sauced in a spicy and slightly chocolate-flavored cream ($5.75).

Chalupa San Francisco ($5) was a delicious platter of chilled beans, cheeses, shrimp and guacamole, served with salad fixings on a chalupa pastry. But there wasn't enough of this delightful dish for the price charged.

Dessert appeased us. The flan eaters reveled in Mariachi's offering ($1.50). My husband and I found happiness in the dark Mexican coffee ($3). A creamy mixture of tequila, Kahlua and whipped cream, it drained away notions of disappointment.

The bill for four adults and two kids was $54.02.