| Perihelion Passage
 | Designation | Name | Observation Period | Number | 
| 2004 July 10 | 29P | Schwassmann-Wachmann 1 | 1998 Dec.  5 - 2000 Feb. 11 | 18 | 
| 2002 Feb. 13 | C/1999 F1 | Catalina | 1999 May   7 - 1999 May   7 | 1 | 
| 2001 Oct. 28 | C/1999 U4 | Catalina-Skiff | 1999 Nov.  4 - 1999 Nov. 28 | 4 | 
| 2001 Mar. 24 | C/1999 Y1 | LINEAR | 1999 Dec. 27 - 2000 Feb.  5 | 6 | 
| 2001 Jan. 15 | 74P | Smirnova-Chernykh | 1998 Dec. 19 - 2000 Jan. 15 | 5 | 
| 2000 Dec. 13 | C/1999 T1 | McNaught-Hartley | 1999 Oct. 20 - 1999 Oct. 20 | 1 | 
| 2000 Nov. 24 | C/1999 T2 | LINEAR | 1999 Oct. 17 - 2000 Jan.  8 | 6 | 
| 2000 Sept. 1 | C/1999 T3 | LINEAR | 1999 Nov.  4 - 1999 Nov. 13 | 3 | 
| 2000 July 26 | C/1999 S4 | LINEAR | 1999 Oct.  2 - 2000 Feb. 12 | 24 | 
| 2000 July  4 | C/1999 K5 | LINEAR | 1999 May  31 - 1999 July 31 | 5 | 
| 2000 Apr. 24 | C/1999 K8 | Skiff | 1999 May  17 - 2000 Jan. 28 | 13 | 
| 2000 Apr.  5 | C/1999 J2 | Hergenrother | 2000 Feb. 11 - 2000 Feb. 11 | 1 | 
| 2000 Mar. 19 | P/2000 C1 | LINEAR | 1999 May  31 - 1999 Dec. 30 | 17 | 
| 2000 Jan. 11 | 114P | Wiseman-Skiff | 1999 Oct. 10 - 2000 Feb. 12 | 18 | 
| 2000 Jan.  4 | C/1999 L3 | LINEAR | 1999 Nov. 29 - 2000 Feb. 17 | 24 | 
| 2000 Jan.  2 | 9P | Tempel 1 | 2000 Feb. 11 - 2000 Feb. 11 | 1 | 
| 1999 Dec. 27 | 63P | Wild 1 | 1999 Nov.  8 - 2000 Feb. 11 | 10 | 
| 1999 Dec. 16 | 106P | Schuster | 1999 Oct. 20 - 2000 Feb.  5 | 9 | 
| 1999 Dec. 10 | 135P | Shoemaker-Levy 8 | 1999 Feb. 22 - 1999 Feb. 22 | 1 | 
| 1999 Dec.  9 | 141P | Machholz 2 | 1999 Oct. 24 - 2000 Jan. 22 | 18 | 
| 1999 Nov. 27 | C/1997 BA6 | Spacewatch | 1998 Dec.  5 - 1998 Dec.  5 | 1 | 
| 1999 Nov. 18 | P/1999 U3 | LINEAR | 1999 Nov.  4 - 2000 Feb. 12 | 7 | 
| 1999 Nov.  9 | C/1999 S3 | LINEAR | 1999 Sept.25 - 2000 Feb. 11 | 23 | 
| 1999 Sept.20 | C/1999 J3 | LINEAR | 1999 May  17 - 1999 Oct. 24 | 19 | 
| 1999 Sept.16 | 59P | Kearns-Kwee | 1999 Oct. 17 - 1999 Dec. 29 | 4 | 
| 1999 Sept. 8 | 10P | Tempel 2 | 1999 Jan. 22 - 1999 Dec. 23 | 18 | 
| 1999 Aug. 25 | 84P | Giclas | 1999 Oct. 10 - 2000 Jan.  3 | 4 | 
| 1999 Aug. 18 | C/1999 H3 | LINEAR | 1999 Apr. 27 - 2000 Feb. 17 | 28 | 
| 1999 Aug.  6 | C/1999 XS87 | LINEAR | 2000 Jan. 15 - 2000 Feb.  5 | 2 | 
| 1999 Aug.  4 | C/1999 L2 | LINEAR | 1999 June 30 - 1999 June 30 | 1 | 
| 1999 Aug.  3 | 50P | Arend | 1999 Sept. 4 - 1999 Sept.20 | 2 | 
| 1999 July 24 | C/1999 K6 | LINEAR | 1999 May  31 - 1999 Oct. 11 | 13 | 
| 1999 July 23 | C/1999 N2 | Lynn | 1999 July 24 - 1999 Dec.  9 | 11 | 
| 1999 July 11 | C/1999 H1 | Lee | 1999 May   6 - 1999 Dec. 10 | 39 | 
| 1999 June 25 | C/1998 T1 | LINEAR | 1998 Oct. 18 - 2000 Feb. 11 | 16 | 
| 1999 May  14 | 140P | Bowell-Skiff | 1999 Jan.  5 - 1999 May   1 | 7 | 
| 1999 May   6 | 4P | Faye | 1998 Nov. 23 - 2000 Feb.  9 | 9 | 
| 1999 May   4 | 37P | Forbes | 1999 Apr.  8 - 1999 Oct. 11 | 20 | 
| 1999 Apr. 10 | C/1999 K2 | Ferris | 1999 May  31 - 1999 May  31 | 1 | 
| 1999 Apr.  6 | 105P | Singer Brewster | 1999 Apr. 16 - 1999 Apr. 16 | 1 | 
| 1999 Mar. 10 | P/1998 U3 | Jager | 1998 Nov.  7 - 1999 May  12 | 11 | 
| 1999 Mar.  8 | 60P | Tsuchinshan 2 | 1998 Dec. 24 - 1999 Mar. 22 | 4 | 
| 1999 Feb. 27 | C/1999 K3 | LINEAR | 1999 May  31 - 1999 May  31 | 1 | 
| 1999 Feb. 26 | P/1998 U4 | Spahr | 1999 Feb.  6 - 1999 Feb.  6 | 1 | 
| 1999 Feb. 18 | P/1999 D1 | Hermann | 1999 Feb. 22 - 1999 Mar. 22 | 3 | 
| 1999 Jan. 31 | C/1999 E1 | Li | 1999 Mar. 22 - 2000 Jan. 28 | 7 | 
| 1999 Jan. 29 | C/1999 A1 | Tilbrook | 1999 Jan. 15 - 1999 Jan. 16 | 2 | 
| 1999 Jan. 27 | 52P | Harrington-Abell | 1999 Mar. 13 - 1999 May   7 | 7 | 
| 1999 Jan. 24 | C/1998 M5 | LINEAR | 1998 Sept.12 - 2000 Jan. 28 | 32 | 
| 1999 Jan. 17 | P/1998 W1 | Spahr | 1998 Nov. 24 - 1999 Mar. 22 | 12 | 
| 1998 Dec. 21 | C/1998 U5 | LINEAR | 1998 Nov.  7 - 1999 June  4 | 13 | 
| 1998 Dec. 17 | P/1998 Y2 | Li | 1999 Jan.  3 - 1999 Mar. 16 | 4 | 
| 1998 Nov. 21 | C/1998 Y1 | LINEAR | 1998 Dec. 25 - 1999 Feb.  7 | 5 | 
| 1998 Nov. 21 | 21P | Giacobini-Zinner | 1998 Oct. 25 - 1999 May   7 | 10 | 
| 1998 Nov. 18 | 134P | Kowal-Vavrova | 1999 June 11 - 1999 June 14 | 2 | 
| 1998 Nov.  2 | P/1998 VS24 | LINEAR | 1998 Dec. 26 - 1999 Jan. 16 | 2 | 
| 1998 Nov.  2 | P/1998 S1 | LINEAR-Mueller | 1998 Dec. 12 - 1999 Mar. 16 | 3 | 
| 1998 Oct. 28 | C/1998 M1 | LINEAR | 1999 Mar. 22 - 1999 May   7 | 2 | 
| 1998 Oct. 20 | P/1998 U2 | Mueller | 1998 Dec. 12 - 1998 Dec. 12 | 1 | 
| 1998 Oct. 17 | C/1998 P1 | Williams | 1999 Mar. 13 - 1999 May  12 | 7 | 
| 1998 Oct. 14 | 93P | Lovas 1 | 1998 Nov. 19 - 1999 Mar. 22 | 25 | 
| 1998 Oct.  6 | P/1998 QP54 | LONEOS-Tucker | 1998 Dec. 12 - 1998 Dec. 12 | 1 | 
| 1998 Oct.  6 | C/1998 W3 | LINEAR | 1998 Nov. 28 - 1999 Mar. 22 | 12 | 
| 1998 Sept.28 | 139P | Vaisala-Oterma | 1998 Dec. 11 - 1998 Dec. 11 | 1 | 
| 1998 Sept.27 | 88P | Howell | 1998 Nov.  1 - 1999 Feb.  6 | 6 | 
| 1998 Sept. 2 | C/1999 U1 | Ferris | 1999 Oct. 20 - 1999 Nov. 13 | 3 | 
| 1998 Sept. 1 | C/1998 K1 | Mueller | 1998 Dec. 24 - 1999 Mar. 22 | 5 | 
| 1998 Aug. 23 | C/1999 F2 | Dalcanton | 1999 June 10 - 1999 June 30 | 4 | 
| 1998 Aug. 13 | C/1998 M2 | LINEAR | 1998 Dec. 12 - 1999 May   7 | 3 | 
| 1998 July 31 | C/1999 G1 | LINEAR | 1999 Apr. 13 - 1999 May   7 | 2 | 
| 1998 July 20 | P/1998 X1 | ODAS | 1998 Dec. 20 - 1999 Mar. 22 | 4 | 
| 1998 July 17 | C/1998 K5 | LINEAR | 1998 June 20 - 1999 Jan. 16 | 3 | 
| 1998 July 17 | C/1998 M3 | Larsen | 1999 Feb. 22 - 1999 Apr. 13 | 3 | 
| 1998 July 12 | 49P | Arend-Rigaux | 1999 Jan. 30 - 1999 Jan. 30 | 1 | 
| 1998 Mar. 10 | C/1997 J2 | Meunier-Dupouy | 1998 Mar.  7 - 1998 Dec. 13 | 4 | 
| 1997 Dec. 12 | 69P | Taylor | 1998 Mar.  7 - 1998 Mar.  7 | 1 | 
| 1996 July 24 | 65P | Gunn | 1998 Dec. 19 - 1999 Feb.  6 | 2 | 
| 1996 Feb. 14 | 95P | Chiron | 1998 Mar.  7 - 1999 June 12 | 6 |