Between the 2003 and 2007 seasons, the Kansas City Royals and the Tampa Bay Devil Rays were tied for losing the most games, with 482 losses.

Interpreted as:

most regular-season losses by a team from 2003 to 2007

	TEAM	L	W	L%	G	W%	AB	R	H	2B	3B	HR	RBI	BB	HBP	SO	SB	CS	PA	TB	XBH	SH	SF	IBB	GIDP	AVG	OBP	SLG	OPS
1	Royals	482	328	.595	810	.405	27,732	3,720	7,365	1,473	185	664	3,487	2,263	367	5,100	383	201	30,844	11,200	2,322	242	240	149	678	.266	.327	.404	.730
2	Devil Rays	482	327	.596	809	.404	27,756	3,650	7,331	1,423	193	816	3,480	2,287	280	5,394	690	233	30,745	11,588	2,432	170	252	158	558	.264	.324	.417	.741
3	Pirates	460	349	.569	809	.431	27,764	3,528	7,290	1,442	170	733	3,365	2,337	414	5,542	358	160	31,080	11,271	2,345	336	229	193	642	.263	.327	.406	.733
4	Orioles	448	362	.553	811	.447	28,193	3,838	7,707	1,486	119	816	3,643	2,380	285	4,570	538	188	31,305	11,879	2,421	215	232	163	678	.273	.334	.421	.755
5	Tigers	441	369	.544	810	.456	28,090	3,850	7,564	1,414	228	902	3,673	2,249	251	5,468	413	211	31,050	12,140	2,544	235	225	152	609	.269	.327	.432	.759
6	Reds	440	370	.543	811	.457	27,714	3,796	7,097	1,445	99	1,019	3,631	2,884	347	6,269	450	146	31,428	11,797	2,563	303	180	217	605	.256	.332	.426	.757
7	Rockies	436	375	.538	811	.462	27,890	4,099	7,575	1,579	189	878	3,897	2,879	288	5,678	357	183	31,697	12,166	2,646	442	198	248	656	.272	.344	.436	.780
8	Nationals	435	375	.537	810	.463	27,352	3,404	6,984	1,512	137	699	3,243	2,627	291	5,289	446	207	30,880	10,867	2,348	402	208	268	649	.255	.325	.397	.722
9	Brewers	435	374	.538	809	.462	27,466	3,605	7,049	1,499	132	917	3,444	2,621	370	6,065	483	182	30,977	11,563	2,548	302	218	253	660	.257	.327	.421	.748
10	Diamondbacks	432	378	.533	810	.467	27,707	3,513	7,143	1,506	190	809	3,378	2,614	259	5,198	381	150	31,131	11,456	2,505	306	245	237	652	.258	.325	.413	.738
11	Mariners	419	391	.517	810	.483	28,144	3,742	7,630	1,405	151	730	3,531	2,337	280	4,868	507	193	31,159	11,527	2,286	189	209	214	647	.271	.331	.410	.740
12	Rangers	416	394	.514	810	.486	28,209	4,202	7,557	1,563	158	1,088	4,025	2,491	280	5,548	342	125	31,334	12,700	2,809	131	223	154	606	.268	.331	.450	.781
13	Blue Jays	406	403	.502	809	.498	27,905	3,950	7,523	1,646	157	835	3,765	2,592	360	5,069	289	146	31,212	11,988	2,638	101	254	146	704	.270	.337	.430	.766
14	Mets	404	405	.499	809	.501	27,541	3,686	7,126	1,447	144	861	3,509	2,583	279	5,321	676	175	30,995	11,444	2,452	370	222	272	596	.259	.326	.416	.742
15	Marlins	404	406	.499	810	.501	27,607	3,734	7,363	1,522	188	816	3,526	2,544	338	5,445	557	247	31,093	11,709	2,526	389	215	243	616	.267	.334	.424	.758
16	Cubs	403	407	.498	810	.502	27,961	3,684	7,471	1,544	150	918	3,508	2,295	221	5,140	411	180	31,041	12,069	2,612	359	205	207	648	.267	.326	.432	.757
17	Padres	401	410	.494	811	.506	27,794	3,602	7,252	1,450	172	729	3,420	2,852	251	5,293	405	163	31,441	11,233	2,351	297	247	202	632	.261	.332	.404	.737
18	Giants	395	413	.489	808	.511	27,474	3,683	7,192	1,458	177	785	3,487	2,755	253	4,553	344	153	31,095	11,359	2,420	406	207	408	697	.262	.332	.413	.746
19	Indians	395	415	.488	810	.512	28,080	4,028	7,580	1,634	139	923	3,863	2,721	328	5,570	369	216	31,558	12,261	2,696	194	235	197	640	.270	.339	.437	.776
20	Dodgers	391	419	.483	810	.517	27,675	3,575	7,248	1,353	169	758	3,421	2,596	293	4,994	505	211	31,084	11,213	2,280	321	199	220	637	.262	.330	.405	.735
21	Astros	387	423	.478	811	.522	27,639	3,759	7,188	1,451	155	880	3,581	2,760	342	5,176	414	173	31,377	11,589	2,486	418	218	235	633	.260	.332	.419	.752
22	White Sox	380	430	.469	810	.531	27,648	3,958	7,303	1,380	101	1,088	3,808	2,487	310	5,153	463	240	30,908	12,149	2,569	239	224	145	629	.264	.329	.439	.769
23	Phillies	376	434	.464	810	.536	28,103	4,195	7,523	1,530	167	977	3,992	3,202	354	5,779	518	127	32,179	12,318	2,674	294	226	333	590	.268	.347	.438	.786
24	Twins	370	440	.457	810	.543	27,966	3,788	7,570	1,445	171	741	3,559	2,512	284	4,698	525	206	31,191	11,580	2,357	195	234	214	736	.271	.334	.414	.749
25	Athletics	366	444	.452	810	.548	27,929	3,845	7,278	1,524	97	866	3,679	3,015	265	4,873	239	98	31,566	11,594	2,487	109	248	171	720	.261	.336	.415	.751