The Arizona Diamondbacks had the lowest winning percentage by a team in 2004, winning 31.5 percent of the time.

	TEAM	W%	SEASON	W	L	G	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Diamondbacks	.315	2004	51	111	162	5,544	615	1,401	295	38	135	582	441	35	1,022	53	32	6,113	2,177	468	56	37	38	137	.253	.310	.393	.703
2	Royals	.358	2004	58	104	162	5,538	720	1,432	261	29	150	675	461	76	1,057	67	48	6,153	2,201	440	40	38	28	130	.259	.322	.397	.720
3	Mariners	.389	2004	63	99	162	5,722	698	1,544	276	20	136	658	492	54	1,058	110	42	6,362	2,268	432	46	48	49	131	.270	.331	.396	.727
4	Expos	.414	2004	67	95	162	5,474	635	1,361	276	27	151	605	496	35	925	109	38	6,138	2,144	454	100	33	51	115	.249	.313	.392	.705
5	Brewers	.416	2004	67	94	161	5,483	634	1,358	295	32	135	601	540	68	1,312	138	40	6,187	2,122	462	56	40	49	120	.248	.321	.387	.708
6	Blue Jays	.416	2004	67	94	161	5,531	719	1,438	290	34	145	680	513	71	1,083	58	31	6,177	2,231	469	20	42	25	139	.260	.328	.403	.732
7	Rockies	.420	2004	68	94	162	5,577	833	1,531	331	34	202	795	568	54	1,181	44	33	6,333	2,536	567	97	37	51	132	.275	.345	.455	.800
8	Devil Rays	.435	2004	70	91	161	5,483	714	1,416	278	46	145	685	469	55	944	132	42	6,098	2,221	469	35	56	33	97	.258	.320	.405	.725
9	Mets	.438	2004	71	91	162	5,532	684	1,376	289	20	185	658	512	61	1,159	107	23	6,208	2,260	494	69	34	54	129	.249	.317	.409	.726
10	Tigers	.444	2004	72	90	162	5,623	827	1,531	284	54	201	800	518	50	1,144	86	50	6,284	2,526	539	50	43	32	110	.272	.337	.449	.786
11	Pirates	.447	2004	72	89	161	5,483	680	1,428	267	39	142	648	415	95	1,066	63	40	6,114	2,199	448	79	42	33	117	.260	.321	.401	.722
12	Reds	.469	2004	76	86	162	5,518	750	1,380	287	28	194	713	599	81	1,335	77	25	6,278	2,305	509	55	25	38	125	.250	.331	.418	.749
13	Orioles	.481	2004	78	84	162	5,736	842	1,614	319	18	169	803	528	57	949	101	41	6,429	2,476	506	46	62	34	126	.281	.345	.432	.776
14	Indians	.494	2004	80	82	162	5,676	858	1,565	345	29	184	820	606	78	1,009	94	55	6,449	2,520	558	47	42	41	143	.276	.351	.444	.795
15	White Sox	.512	2004	83	79	162	5,534	865	1,481	284	19	242	823	499	63	1,030	78	51	6,196	2,529	545	58	42	25	119	.268	.333	.457	.790
16	Marlins	.512	2004	83	79	162	5,486	718	1,447	275	32	148	677	499	58	968	96	43	6,160	2,230	455	77	40	37	142	.264	.329	.406	.736
17	Phillies	.531	2004	86	76	162	5,643	840	1,505	303	23	215	802	645	58	1,133	100	27	6,456	2,499	541	64	46	60	123	.267	.345	.443	.788
18	Padres	.537	2004	87	75	162	5,573	768	1,521	304	32	139	722	566	56	910	52	25	6,313	2,306	475	52	66	45	128	.273	.342	.414	.756
19	Cubs	.549	2004	89	73	162	5,628	789	1,508	308	29	235	755	489	38	1,080	66	28	6,281	2,579	572	78	48	46	120	.268	.328	.458	.786
20	Rangers	.549	2004	89	73	162	5,615	860	1,492	323	34	227	825	500	61	1,099	69	36	6,256	2,564	584	23	57	41	91	.266	.329	.457	.786
21	Giants	.562	2004	91	71	162	5,546	850	1,500	314	33	183	805	705	72	874	43	23	6,466	2,429	530	92	51	153	142	.270	.357	.438	.795
22	Athletics	.562	2004	91	71	162	5,728	793	1,545	336	15	189	752	608	55	1,061	47	22	6,459	2,478	540	25	43	40	142	.270	.343	.433	.776
23	Twins	.568	2004	92	70	162	5,623	780	1,494	310	24	191	735	513	64	982	116	46	6,286	2,425	525	46	40	42	130	.266	.332	.431	.763
24	Angels	.568	2004	92	70	162	5,675	836	1,603	272	37	162	783	450	73	942	143	46	6,295	2,435	471	56	41	43	123	.282	.341	.429	.770
25	Astros	.568	2004	92	70	162	5,468	803	1,458	294	36	187	756	590	61	999	89	30	6,269	2,385	517	98	52	54	128	.267	.342	.436	.778