Thirty-four monosubstituted ortho-, and para-phenylsulfamates have been synthesized, characterized and tasted. The compounds (as sodium salts) display all four primary tastes often in combination.Some structure-sweet taste relationships have been derived using measurements made with CPK models and using Hammett sigma values for the various substituents.For the 14 meta-substituted compounds (including five previously made) those having x (the length of the aromatic portion including the substituent) in the range 5.82 +/- 0.12 Angstrom and V-CPK (= x.y.z.) less than or equal to 295 Angstrom(3) displayed some sweetness, this being much more pronounced and exclusive for those compounds with V-CPK less than or equal to 170 Angstrom(3). All the sweet meta-compounds had sigma(m) in the range -0.07 to + 0.56. The ortho-compounds that showed some sweet component in their taste generally had sigma(o) in the range -0.30 to + 0.81 and the para-compounds nine of which had a sweet aftertaste had sigma(p) in the range -0.27 to + 0.66.