best whip as a pitcher in a month with a minimum of 40 innings pitched in the 1990's

Between the 1990 and 1999 seasons, Pedro Martinez had the lowest WHIP when pitching at least 40 innings in a month, with a WHIP of 0.63 in September 1999.

	NAME	WHIP	IP	MONTH	G	W	L	W%	GS	ERA	SO	CG	SHO	SV	H	ER	R	HR	BB	HBP	GF	IBB	TBF	WP	K/9	BB/9	K/BB	HR/9	K%	BB%	BABIP	RA	H/9
1	Pedro Martinez P. Martinez	0.63	41.0	September 1999	5	4	0	1.000	5	0.88	70	2	1	0	20	4	5	1	6	3	0	0	150	1	15.37	1.32	11.67	0.22	46.7	4.0	.271	1.10	4.39
2	Bret Saberhagen B. Saberhagen	0.66	41.0	August 1991	5	3	1	.750	5	0.88	31	3	2	0	20	4	4	1	7	0	0	1	144	0	6.80	1.54	4.43	0.22	21.5	4.9	.181	0.88	4.39
3	Kevin Millwood K. Millwood	0.68	47.0	August 1999	6	2	2	.500	6	2.49	43	0	0	0	22	13	14	8	10	0	0	0	173	0	8.23	1.91	4.30	1.53	24.9	5.8	.125	2.68	4.21
4	Roger Clemens R. Clemens	0.70	50.0	August 1998	6	4	0	1.000	6	0.90	68	3	3	0	25	5	7	0	10	0	0	0	184	0	12.24	1.80	6.80	0.00	37.0	5.4	.236	1.26	4.50
5	Andy Benes A. Benes	0.70	41.1	August 1991	6	5	0	1.000	6	2.40	31	1	1	0	23	11	11	3	6	1	0	0	151	0	6.75	1.31	5.17	0.65	20.5	4.0	.182	2.40	5.01
6	Zane Smith Z. Smith	0.73	41.0	September 1990	5	3	1	.750	5	0.66	30	3	2	0	26	3	9	1	4	0	0	1	147	0	6.59	0.88	7.50	0.22	20.4	2.7	.223	1.98	5.71
7	Danny Darwin D. Darwin	0.74	40.2	May 1993	6	5	0	1.000	6	1.33	26	0	0	0	24	6	7	1	6	0	0	0	151	1	5.75	1.33	4.33	0.22	17.2	4.0	.195	1.55	5.31
8	Randy Johnson R. Johnson	0.74	43.0	September 1993	5	4	0	1.000	5	1.67	60	2	1	0	19	8	8	2	13	2	0	0	162	1	12.56	2.72	4.62	0.42	37.0	8.0	.200	1.67	3.98
9	Shane Reynolds S. Reynolds	0.75	48.0	August 1996	6	4	1	.800	6	1.88	34	2	0	0	33	10	11	4	3	1	0	0	178	1	6.38	0.56	11.33	0.75	19.1	1.7	.213	2.06	6.19
10	Mark Gardner M. Gardner	0.75	40.0	July 1990	5	2	1	.667	5	1.35	40	2	2	0	19	6	6	1	11	2	0	0	147	0	9.00	2.47	3.64	0.23	27.2	7.5	.194	1.35	4.27
11	Kevin Brown K. Brown	0.76	47.1	August 1996	6	5	1	.833	6	1.71	42	1	0	0	32	9	10	4	4	1	0	1	178	2	7.99	0.76	10.50	0.76	23.6	2.2	.220	1.90	6.08
12	Kevin Brown K. Brown	0.76	42.0	June 1990	5	4	1	.800	5	1.50	19	4	1	0	27	7	9	1	5	1	0	1	161	1	4.07	1.07	3.80	0.21	11.8	3.1	.193	1.93	5.79
13	Greg Maddux G. Maddux	0.77	49.2	July 1995	6	4	0	1.000	6	1.27	49	3	0	0	33	7	7	1	5	1	0	1	186	0	8.88	0.91	9.80	0.18	26.3	2.7	.246	1.27	5.98
14	Greg Maddux G. Maddux	0.77	44.1	May 1995	6	3	1	.750	6	2.44	37	2	0	0	29	12	13	1	5	1	0	0	166	0	7.51	1.02	7.40	0.20	22.3	3.0	.230	2.64	5.89
15	Roger Clemens R. Clemens	0.77	43.0	September 1991	5	4	0	1.000	5	1.67	36	3	2	0	29	8	8	1	4	1	0	1	159	0	7.53	0.84	9.00	0.21	22.6	2.5	.239	1.67	6.07
16	Kevin Tapani K. Tapani	0.77	40.1	June 1991	5	3	1	.750	5	1.56	19	1	0	0	29	7	9	3	2	0	0	0	148	0	4.24	0.45	9.50	0.67	12.8	1.4	.210	2.01	6.47
17	Jeff Fassero J. Fassero	0.77	48.0	June 1996	6	5	0	1.000	6	1.88	42	1	1	0	28	10	12	6	9	2	0	0	184	1	7.88	1.69	4.67	1.13	22.8	4.9	.176	2.25	5.25
18	Greg Maddux G. Maddux	0.79	42.0	July 1994	5	3	2	.600	5	1.07	31	3	0	0	30	5	9	0	3	1	0	0	159	0	6.64	0.64	10.33	0.00	19.5	1.9	.242	1.93	6.43
19	Greg Maddux G. Maddux	0.80	49.0	June 1998	6	4	0	1.000	6	1.29	45	4	2	0	36	7	9	1	3	1	0	0	182	1	8.27	0.55	15.00	0.18	24.7	1.6	.265	1.65	6.61
20	Randy Johnson R. Johnson	0.80	49.0	June 1997	6	4	1	.800	6	0.92	68	2	1	0	25	5	8	3	14	1	0	0	180	0	12.49	2.57	4.86	0.55	37.8	7.8	.234	1.47	4.59
21	Roger Clemens R. Clemens	0.80	51.0	May 1992	6	5	1	.833	6	1.76	35	3	2	0	33	10	10	2	8	2	0	2	186	0	6.18	1.41	4.38	0.35	18.8	4.3	.223	1.76	5.82
22	Greg Maddux G. Maddux	0.81	48.1	April 1994	6	4	2	.667	6	1.12	37	2	1	0	32	6	9	1	7	0	0	0	178	3	6.89	1.30	5.29	0.19	20.8	3.9	.233	1.68	5.96
23	Tommy Greene T. Greene	0.81	43.1	May 1993	5	5	0	1.000	5	1.45	35	4	1	0	27	7	8	2	8	0	0	0	163	2	7.27	1.66	4.38	0.42	21.5	4.9	.212	1.66	5.61
24	Danny Darwin D. Darwin	0.81	43.1	July 1990	6	4	0	1.000	6	1.04	28	1	0	0	28	5	5	2	7	1	0	1	164	0	5.82	1.45	4.00	0.42	17.1	4.3	.206	1.04	5.82
25	Orel Hershiser O. Hershiser	0.81	42.0	May 1998	6	5	0	1.000	6	0.86	27	0	0	0	19	4	5	1	15	1	0	1	157	3	5.79	3.21	1.80	0.21	17.2	9.6	.159	1.07	4.07