Between the 2004 and 2008 seasons, the Kansas City Royals lost the most games by a team, with 490 losses.

Interpreted as:

most regular-season losses by a team from 2004 to 2008

	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	490	320	.605	810	.395	27,772	3,575	7,346	1,488	174	622	3,356	2,179	342	5,179	342	197	30,723	11,048	2,284	211	219	148	694	.265	.323	.398	.721
2	Pirates	468	341	.578	809	.422	27,811	3,510	7,252	1,481	146	723	3,359	2,282	386	5,532	329	142	31,044	11,194	2,350	323	242	191	641	.261	.323	.403	.725
3	Nationals	458	351	.566	809	.434	27,406	3,334	6,956	1,487	138	672	3,169	2,639	313	5,394	427	211	30,956	10,735	2,297	394	204	231	659	.254	.324	.392	.716
4	Mariners	451	359	.557	810	.443	28,226	3,618	7,619	1,400	138	715	3,403	2,168	265	4,769	489	188	31,054	11,440	2,253	190	205	224	654	.270	.326	.405	.731
5	Orioles	450	359	.556	809	.444	28,087	3,877	7,677	1,531	125	836	3,698	2,482	273	4,658	530	189	31,273	11,966	2,492	191	240	168	666	.273	.336	.426	.762
6	Rays	448	361	.554	809	.446	27,643	3,709	7,273	1,409	192	859	3,537	2,493	292	5,588	690	241	30,843	11,643	2,460	161	254	145	561	.263	.328	.421	.749
7	Rockies	436	375	.538	811	.462	27,929	3,993	7,565	1,559	186	840	3,797	2,830	293	5,753	435	183	31,727	12,016	2,585	477	198	238	635	.271	.342	.430	.772
8	Reds	435	375	.537	811	.463	27,670	3,806	7,099	1,475	102	1,024	3,639	2,920	318	6,068	455	159	31,406	11,850	2,601	309	189	233	604	.257	.332	.428	.761
9	Diamondbacks	434	376	.536	810	.464	27,546	3,516	7,031	1,521	190	816	3,365	2,670	263	5,479	363	135	31,026	11,380	2,527	311	236	223	631	.255	.324	.413	.738
10	Giants	424	385	.524	809	.476	27,561	3,568	7,204	1,488	185	699	3,380	2,614	261	4,617	399	162	31,035	11,159	2,372	387	212	374	706	.261	.329	.405	.734
11	Brewers	413	396	.511	809	.489	27,453	3,641	7,024	1,557	143	919	3,481	2,624	368	6,047	492	181	30,960	11,624	2,619	294	221	256	599	.256	.327	.423	.750
12	Tigers	410	400	.506	810	.494	28,265	4,080	7,781	1,506	230	949	3,900	2,378	248	5,445	378	179	31,311	12,594	2,685	200	220	151	639	.275	.335	.446	.780
13	Marlins	410	399	.507	809	.493	27,616	3,753	7,301	1,532	172	867	3,558	2,572	350	5,838	483	201	31,114	11,778	2,571	356	220	249	600	.264	.332	.426	.759
14	Rangers	408	402	.504	810	.496	28,273	4,277	7,670	1,665	157	1,043	4,093	2,598	268	5,703	358	125	31,518	12,778	2,865	144	235	166	608	.271	.336	.452	.788
15	Blue Jays	406	403	.502	809	.498	27,747	3,770	7,396	1,592	156	771	3,593	2,567	329	4,926	332	148	31,035	11,613	2,519	138	254	140	708	.267	.333	.419	.752
16	Padres	402	409	.496	811	.504	27,831	3,561	7,200	1,457	167	755	3,394	2,805	247	5,479	365	141	31,440	11,256	2,379	306	251	203	619	.259	.329	.404	.734
17	Cubs	393	416	.486	809	.514	28,030	3,815	7,592	1,571	147	930	3,628	2,439	221	5,168	425	183	31,238	12,247	2,648	344	204	215	647	.271	.332	.437	.769
18	Dodgers	392	418	.484	810	.516	27,723	3,701	7,375	1,364	173	771	3,536	2,732	264	5,041	551	218	31,242	11,398	2,308	314	209	239	669	.266	.335	.411	.746
19	Braves	389	421	.480	810	.520	27,932	3,984	7,542	1,568	160	890	3,820	2,799	247	5,583	352	156	31,549	12,100	2,618	352	219	254	680	.270	.339	.433	.773
20	Astros	387	422	.478	810	.522	27,507	3,666	7,154	1,427	147	856	3,502	2,652	313	5,206	462	195	31,107	11,443	2,430	414	221	233	624	.260	.330	.416	.746
21	Athletics	386	423	.477	809	.523	27,883	3,723	7,198	1,477	96	815	3,547	3,033	254	5,201	279	105	31,517	11,312	2,388	117	230	142	728	.258	.334	.406	.740
22	Indians	382	428	.472	810	.528	28,051	4,134	7,622	1,677	135	936	3,975	2,815	369	5,721	360	184	31,669	12,377	2,748	191	243	216	635	.272	.343	.441	.785
23	Mets	382	428	.472	810	.528	27,806	3,843	7,300	1,459	158	909	3,653	2,713	264	5,310	744	180	31,374	11,802	2,526	365	226	301	589	.263	.331	.424	.756
24	White Sox	378	433	.466	811	.534	27,714	3,978	7,316	1,373	95	1,103	3,827	2,508	315	5,253	453	245	30,991	12,188	2,571	224	230	151	654	.264	.330	.440	.769
25	Twins	373	438	.460	811	.540	27,952	3,816	7,575	1,425	175	697	3,595	2,529	257	4,650	533	204	31,197	11,441	2,297	205	254	226	739	.271	.334	.409	.744