— || August 5, 1999 || Mallorca || Á. López J., R. Pacheco || — || align=right | 3.6 km || |-id=655 bgcolor=#E9E9E9 | 21655 Niklauswirth || || || August 8, 1999 || Ondřejov || L. Kotková || — || align=right | 6.6 km || |-id=656 bgcolor=#E9E9E9 | 21656 Knuth || || || August 9, 1999 || Ondřejov || P. Pravec, P. Kušnirák || — || align=right | 6.3 km || |-id=657 bgcolor=#fefefe | 21657 || || — || August 10, 1999 || Reedy Creek || J. Broughton || V || align=right | 2.2 km || |-id=658 bgcolor=#fefefe | 21658 || || — || August 10, 1999 || Reedy Creek || J. Broughton || — || align=right | 2.2 km || |-id=659 bgcolor=#E9E9E9 | 21659 Fredholm || || || August 13, 1999 || Prescott || P. G. Comba || — || align=right | 3.4 km || |-id=660 bgcolor=#E9E9E9 | 21660 Velenia || || || August 20, 1999 || Ondřejov || P. Pravec || PAD || align=right | 6.0 km || |-id=661 bgcolor=#fefefe | 21661 Olgagermani || 1999 RA || || September 1, 1999 || Ceccano || G. Masi || ERI || align=right | 5.7 km || |-id=662 bgcolor=#E9E9E9 | 21662 Benigni || 1999 RC || || September 1, 1999 || Stroncone || Santa Lucia Obs. || EUN || align=right | 4.9 km || |-id=663 bgcolor=#d6d6d6 | 21663 Banat || 1999 RM || || September 3, 1999 || Starkenburg Observatory || Starkenburg Obs. || EMA || align=right | 11 km || |-id=664 bgcolor=#E9E9E9 | 21664 Konradzuse || || || September 4, 1999 || Ondřejov || L. Kotková || — || align=right | 4.2 km || |-id=665 bgcolor=#fefefe | 21665 Frege || || || September 5, 1999 || Prescott || P. G. Comba || — || align=right | 2.2 km || |-id=666 bgcolor=#E9E9E9 | 21666 || || — || September 5, 1999 || Višnjan Observatory || K. Korlević || MIS || align=right | 7.3 km || |-id=667 bgcolor=#fefefe | 21667 || || — || September 6, 1999 || Višnjan Observatory || K. Korlević || — || align=right | 2.9 km || |-id=668 bgcolor=#fefefe | 21668 || || — || September 3, 1999 || Kitt Peak || Spacewatch || — || align=right | 5.9 km || |-id=669 bgcolor=#fefefe | 21669 || || — || September 4, 1999 || Kitt Peak || Spacewatch || — || align=right | 2.4 km || |-id=670 bgcolor=#fefefe |