New analogues of deltorphin I (DT I), in which the phenylalanine residue in position 3 is substituted with amphiphilic α,α-disubstituted amino acid enantiomers, (R) and (S)-α-hydroxymethylnaphtylalanine, were synthesized and tested for μ and δ opioid receptor affinity and selectivity. Although both analogues have lower affinity to δ receptors than DT I, they both expressed specificity to δreceptors.