Understanding that iPhone SDK dont support NSPredicate which is there for MAC Apps SDK i wrote an Utility Method to do a syntax validation of email.
-(BOOL)validateEmail:(NSString*)email if( (0 != [email rangeOfString:@"@"].length) && (0 != [email rangeOfString:@"."].length) ) { NSMutableCharacterSet *invalidCharSet = [[[[NSCharacterSet alphanumericCharacterSet] invertedSet]mutableCopy]autorelease]; [invalidCharSet removeCharactersInString:@"_-"]; NSRange range1 = [email rangeOfString:@"@" options:NSCaseInsensitiveSearch]; // If username part contains any character other than "." "_" "-" NSString *usernamePart = [email substringToIndex:range1.location]; NSArray *stringsArray1 = [usernamePart componentsSeparatedByString:@"."]; for (NSString *string in stringsArray1) { NSRange rangeOfInavlidChars=[string rangeOfCharacterFromSet: invalidCharSet]; if(rangeOfInavlidChars.length !=0 || [string isEqualToString:@""]) return NO; } NSString *domainPart = [email substringFromIndex:range1.location+1]; NSArray *stringsArray2 = [domainPart componentsSeparatedByString:@"."]; for (NSString *string in stringsArray2) { NSRange rangeOfInavlidChars=[string rangeOfCharacterFromSet:invalidCharSet]; if(rangeOfInavlidChars.length !=0 || [string isEqualToString:@""]) return NO; } return YES; } else // no '@' or '.' present return NO;